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Sample records for nm reactions zaselenie

  1. The photodissociation of oxetane at 193 nm as the reverse of the Paterno-Buchi reaction

    SciTech Connect

    Lee, Shih-Huang

    2009-12-14

    We investigated the photodissociation of oxetane (1,3-trimethylene oxide) at 193.3 nm in a molecular-beam apparatus using photofragment-translational spectroscopy and selective photoionization. We measured time-of-flight (TOF) spectra and angular anisotropy parameters {beta}(t) as a function of flight time of products at m/z=26-30 u utilizing photoionization energies from 9.8 to 14.8 eV. The TOF distributions of the products alter greatly with the employed photon energy, whereas their {beta}(t) distributions are insensitive to the photon energy. Dissociation to H{sub 2}CO+C{sub 2}H{sub 4} is the major channel in the title reaction. Three distinct dissociation paths with branching ratios 0.923:0.058:0.019 are responsible for the three features observed in the distribution of kinetic energy released in the channel H{sub 2}CO+C{sub 2}H{sub 4}. The observation of H{sub 2} and H atoms, {approx}1% in branching, indicates that products H{sub 2}CO and C{sub 2}H{sub 4} spontaneously decompose to only a small extent. Most HCO, C{sub 2}H{sub 3}, and C{sub 2}H{sub 2} ions originate from dissociative photoionization of products H{sub 2}CO and C{sub 2}H{sub 4}. Except atomic H and H{sub 2}, the photoproducts have large angular anisotropies, {beta}{>=}-0.8, which reflects rapid dissociation of oxetane following optical excitation at 193.3 nm. The mechanisms of dissociation of oxetane are addressed. Our results confirm the quantum-chemical calculations of Palmer et al. and provide profound insight into the Paterno-Buchi reaction.

  2. The photodissociation of oxetane at 193 nm as the reverse of the Paterno-Buchi reaction.

    PubMed

    Lee, Shih-Huang

    2009-12-14

    We investigated the photodissociation of oxetane (1,3-trimethylene oxide) at 193.3 nm in a molecular-beam apparatus using photofragment-translational spectroscopy and selective photoionization. We measured time-of-flight (TOF) spectra and angular anisotropy parameters beta(t) as a function of flight time of products at m/z=26-30 u utilizing photoionization energies from 9.8 to 14.8 eV. The TOF distributions of the products alter greatly with the employed photon energy, whereas their beta(t) distributions are insensitive to the photon energy. Dissociation to H(2)CO+C(2)H(4) is the major channel in the title reaction. Three distinct dissociation paths with branching ratios 0.923:0.058:0.019 are responsible for the three features observed in the distribution of kinetic energy released in the channel H(2)CO+C(2)H(4). The observation of H(2) and H atoms, approximately 1% in branching, indicates that products H(2)CO and C(2)H(4) spontaneously decompose to only a small extent. Most HCO, C(2)H(3), and C(2)H(2) ions originate from dissociative photoionization of products H(2)CO and C(2)H(4). Except atomic H and H(2), the photoproducts have large angular anisotropies, beta>or=-0.8, which reflects rapid dissociation of oxetane following optical excitation at 193.3 nm. The mechanisms of dissociation of oxetane are addressed. Our results confirm the quantum-chemical calculations of Palmer et al. and provide profound insight into the Paterno-Buchi reaction.

  3. The photodissociation of oxetane at 193 nm as the reverse of the Paterno-Buchi reaction

    NASA Astrophysics Data System (ADS)

    Lee, Shih-Huang

    2009-12-01

    We investigated the photodissociation of oxetane (1,3-trimethylene oxide) at 193.3 nm in a molecular-beam apparatus using photofragment-translational spectroscopy and selective photoionization. We measured time-of-flight (TOF) spectra and angular anisotropy parameters β(t) as a function of flight time of products at m /z=26-30 u utilizing photoionization energies from 9.8 to 14.8 eV. The TOF distributions of the products alter greatly with the employed photon energy, whereas their β(t) distributions are insensitive to the photon energy. Dissociation to H2CO+C2H4 is the major channel in the title reaction. Three distinct dissociation paths with branching ratios 0.923:0.058:0.019 are responsible for the three features observed in the distribution of kinetic energy released in the channel H2CO+C2H4. The observation of H2 and H atoms, ˜1% in branching, indicates that products H2CO and C2H4 spontaneously decompose to only a small extent. Most HCO, C2H3, and C2H2 ions originate from dissociative photoionization of products H2CO and C2H4. Except atomic H and H2, the photoproducts have large angular anisotropies, β ≥-0.8, which reflects rapid dissociation of oxetane following optical excitation at 193.3 nm. The mechanisms of dissociation of oxetane are addressed. Our results confirm the quantum-chemical calculations of Palmer et al. and provide profound insight into the Paterno-Buchi reaction.

  4. Mathematical model of reaction rate oscillations on a chain of nm-sized catalyst particles

    NASA Astrophysics Data System (ADS)

    Peskov, N. V.; Slinko, M. M.; Jaeger, N. I.

    2003-05-01

    The model of reaction rate oscillations over the surface of nanoparticles embedded into zeolite matrix is numerically investigated. The reaction rate oscillations on each particle are described by a lumped model. The reactions on separate particles interact via the gas diffusion through the pores, which is modeled in the frame of the Maxwell-Stefan approach. The reaction reveals a complex dynamical behavior if a nonhomogeneous distribution of reagent concentrations exists along the chain of particles with a sufficiently large gradient near the ends of the chain.

  5. Novel reactions of quadricyclane: a new route to monomers for low-absorbing polymers in 157-nm photoresists

    NASA Astrophysics Data System (ADS)

    Marsella, John A.; Abdourazak, Atteye H.; Carr, Richard V. C.; Markley, Thomas J.; Robertson, Eric A., III

    2004-05-01

    Norbornene monomers with fluorinated substituents are often used in copolymers targeted for photoresist applications at 157 nm. Homopolymers of these norbornene monomers typically exhibit an absorption coefficient greater than 1.5 μm-1. Comonomers, which are often perfluoroolefins, are needed to meet the transparency requirement for 157 nm lithography, namely an absorption coefficient less than 1.0 μm-1. Clearly, a norbornene monomer that gives a homopolymer with an optical density less than 1.0 μm-1 would require less, if any, perfluoroolefin comonomer, providing a distinct advantage in the production of the base resin. Research in Air Products and Chemicals" labs has led to the discovery that fluorinated hydroxyalkyl ether derivatives of norbornene ring systems with suitable substitution patterns can give homopolymers with absorption coefficients of less than 1 μm-1. The monomers are produced via a novel reaction pathway involving quadricyclane. This pathway provides a versatile and rich synthetic chemistry, and the potential for eliminating, or at least substantially decreasing, perfluoroolefin incorporation into 157 nm photoresists. Specific examples of these reactions are discussed here, along with VUV-VASE and etch resistance data for a series of polymers derived from quadricyclane reactions.

  6. The strong catalytic effect of Pb(II) on the oxygen reduction reaction on 5 nm gold nanoparticles.

    PubMed

    Wang, Ying; Laborda, Eduardo; Plowman, Blake J; Tschulik, Kristina; Ward, Kristopher R; Palgrave, Robert G; Damm, Christine; Compton, Richard G

    2014-02-21

    Citrate-capped gold nanoparticles (AuNPs) of 5 nm in diameter are synthesized via wet chemistry and deposited on a glassy carbon electrode through electrophoresis. The kinetics of the oxygen reduction reaction (ORR) on the modified electrode is determined quantitatively in oxygen-saturated 0.5 M sulphuric acid solution by modelling the cathode as an array of interactive nanoelectrodes. Quantitative analysis of the cyclic voltammetry shows that no apparent ORR electrocatalysis takes place, the kinetics on AuNPs being effectively the same as on bulk gold. Contrasting with the above, a strong ORR catalysis is found when Pb(2+) is added to the oxygen saturated solution or when the modified electrode is cycled in lead alkaline solution such that lead dioxide is repeatedly electrodeposited and stripped off on the nanoparticles. In both cases, the underpotential deposition of lead on the gold nanoparticles is found to be related to the catalysis.

  7. Collision-induced desorption in 193-nm photoinduced reactions in (O{sub 2}+CO) adlayers on Pt(112)

    SciTech Connect

    Han Song; Ma Yunsheng; Matsushima, Tatsuo

    2005-09-01

    The spatial distribution of desorbing O{sub 2} and CO{sub 2} was examined in 193-nm photoinduced reactions in O{sub 2}+CO adlayers on stepped Pt (112)=[(s)3(111)x(001)]. The O{sub 2} desorption collimated in inclined ways in the plane along the surface trough, confirming the hot-atom collision mechanism. In the presence of CO(a), the product CO{sub 2} desorption also collimated in an inclined way, whereas the inclined O{sub 2} desorption was suppressed. The inclined O{sub 2} and CO{sub 2} desorption is explained by a common collision-induced desorption model. At high O{sub 2} coverage, the CO{sub 2} desorption collimated closely along the (111) terrace normal.

  8. Direct Photolysis of Fluoroquinolone Antibiotics at 253.7 nm: Specific Reaction Kinetics and Formation of Equally Potent Fluoroquinolone Antibiotics.

    PubMed

    Snowberger, Sebastian; Adejumo, Hollie; He, Ke; Mangalgiri, Kiranmayi P; Hopanna, Mamatha; Soares, Ana Dulce; Blaney, Lee

    2016-09-06

    Three fluoroquinolone-to-fluoroquinolone antibiotic transformations were monitored during UV-C irradiation processes. In particular, the following reactions were observed: enrofloxacin-to-ciprofloxacin, difloxacin-to-sarafloxacin, and pefloxacin-to-norfloxacin. The apparent molar absorptivity and fluence-based pseudo-first-order rate constants for transformation of the six fluoroquinolones by direct photolysis at 253.7 nm were determined for the pH 2-12 range. These parameters were deconvoluted to calculate specific molar absorptivity and fluence-based rate constants for cationic, zwitterionic, and anionic fluoroquinolone species. For a typical disinfection fluence of 40 mJ/cm(2), the apparent transformation efficiencies were inflated by 2-8% when fluoroquinolone products were not considered; moreover, the overall transformation efficiencies at 400 mJ/cm(2) varied by up to 40% depending on pH. The three product antibiotics, namely ciprofloxacin, sarafloxacin, and norfloxacin, were found to be equally or more potent than the parent fluoroquinolones using an Escherichia coli-based assay. UV treatment of a solution containing difloxacin was found to increase antimicrobial activity due to formation of sarafloxacin. These results highlight the importance of considering antibiotic-to-antibiotic transformations in UV-based processes.

  9. Fundamental study on reaction mechanisms in chemically amplified extreme ultraviolet resists by using 61nm free-electron laser

    NASA Astrophysics Data System (ADS)

    Okamoto, Kazumasa; Kozawa, Takahiro; Hatsui, Takaki; Tajima, Yasuharu; Oikawa, Keita; Nagasono, Mitsuru; Kameshima, Takashi; Togashi, Tadashi; Tono, Kensuke; Yabashi, Makina; Kimura, Hiroaki; Senba, Yasunori; Ohashi, Haruhiko; Sumiyoshi, Takashi

    2011-04-01

    For chemically amplified EUV resists, secondary electrons derived from ionization events play a critical role in the sensitization of acid generators. In this study, we show the dependence of acid generation efficiency on dose rate (fluence per pulse duration) by using 61 nm free-electron laser (FEL) light irradiation. The wavelength of 61 nm (20.3 eV) is applied because single incident photon induces only single ionization event, in contrast to the 13.4 nm EUV photon that induces 4.2 ionization events on average. The acid yield efficiency has enhances with decreasing the dose rate. It is suggested that high density ionization enhances the multiple spur effect.

  10. 248-nm laser photolysis of CHBr3/O-atom mixtures: kinetic evidence for UV CO(A) chemiluminescence in the reaction of methylidyne radicals with atomic oxygen.

    PubMed

    Vaghjiani, Ghanshyam L

    2005-03-17

    The 4th positive and Cameron band emissions from electronically excited CO have been observed for the first time in 248-nm pulsed laser photolysis of a trace amount of CHBr(3) vapor in an excess of O atoms. O atoms were produced by dissociation of N(2)O (or O(2)) in a cw-microwave discharge cavity in 2.0 Torr of He at 298 K. The CO emission intensity in these bands showed a quadratic dependence on the laser fluence employed. Temporal profiles of the CO(A) and other excited-state products that formed in the photoproduced precursor + O-atom reactions were measured by recording their time-resolved chemiluminescence in discrete vibronic bands. The CO 4th positive transition (A(1)Pi, v' = 0 --> X(1)Sigma(+), v' ' = 2) near 165.7 nm was monitored in this work to deduce the pseudo-first-order decay kinetics of the CO(A) chemiluminescence in the presence of various added substrates (CH(4), NO, N(2)O, H(2), and O(2)). From this, the second-order rate coefficient values were determined for reactions of these substrates with the photoproduced precursors. The measured reactivity trends suggest that the prominent precursors responsible for the CO(A) chemiluminescence are the methylidyne radicals, CH(X(2)Pi) and CH(a(4)Sigma(-)), whose production requires the absorption of at least 2 laser photons by the photolysis mixture. The O-atom reactions with brominated precursors (CBr, CHBr, and CBr(2)), which also form in the photolysis, are shown to play a minor role in the production of the CO(A or a) chemiluminescence. However, the CBr(2) + O-atom reaction was identified as a significant source for the 289.9-nm Br(2) chemiluminescence that was also observed in this work. The 282.2-nm OH and the 336.2-nm NH chemiluminescences were also monitored to deduce the kinetics of CH(X(2)Pi) and CH(a(4)Sigma(-)) reactions when excess O(2) and NO were present.

  11. Uniform 2 nm gold nanoparticles supported on iron oxides as active catalysts for CO oxidation reaction: Structure-activity relationship

    SciTech Connect

    Guo, Yu; Senanayake, Sanjaya; Gu, Dong; Jin, Zhao; Du, Pei -Pei; Si, Rui; Xu, Wen -Qian; Huang, Yu -Ying; Tao, Jing; Song, Qi -Sheng; Jia, Chun -Jia; Schueth, Ferdi

    2015-01-12

    Uniform Au nanoparticles (~2 nm) with narrow size-distribution (standard deviation: 0.5–0.6 nm) supported on both hydroxylated (Fe_OH) and dehydrated iron oxide (Fe_O) have been prepared by either deposition-precipitation (DP) or colloidal-deposition (CD) methods. Different structural and textural characterizations were applied to the dried, calcined and used gold-iron oxide samples. The transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) described the high homogeneity in the supported Au nanoparticles. The ex-situ and in-situ X-ray absorption fine structure (XAFS) characterization monitored the electronic and short-range local structure of active gold species. The synchrotron-based in-situ X-ray diffraction (XRD), together with the corresponding temperature-programmed reduction by hydrogen (H₂-TPR), indicated a structural evolution of the iron-oxide supports, correlating to their reducibility. An inverse order of catalytic activity between DP (Au/Fe_OH < Au/Fe_O) and CD (Au/Fe_OH > Au/Fe_O) was observed. Effective gold-support interaction results in a high activity for gold nanoparticles, locally generated by the sintering of dispersed Au atoms on the oxide support in the DP synthesis, while a hydroxylated surface favors the reactivity of externally introduced Au nanoparticles on Fe_OH support for the CD approach. This work reveals why differences in the synthetic protocol translate to differences in the catalytic performance of Au/FeOx catalysts with very similar structural characteristics in CO oxidation.

  12. Uniform 2 nm gold nanoparticles supported on iron oxides as active catalysts for CO oxidation reaction: Structure-activity relationship

    DOE PAGES

    Guo, Yu; Senanayake, Sanjaya; Gu, Dong; ...

    2015-01-12

    Uniform Au nanoparticles (~2 nm) with narrow size-distribution (standard deviation: 0.5–0.6 nm) supported on both hydroxylated (Fe_OH) and dehydrated iron oxide (Fe_O) have been prepared by either deposition-precipitation (DP) or colloidal-deposition (CD) methods. Different structural and textural characterizations were applied to the dried, calcined and used gold-iron oxide samples. The transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) described the high homogeneity in the supported Au nanoparticles. The ex-situ and in-situ X-ray absorption fine structure (XAFS) characterization monitored the electronic and short-range local structure of active gold species. The synchrotron-based in-situ X-ray diffraction (XRD), together with the corresponding temperature-programmed reductionmore » by hydrogen (H₂-TPR), indicated a structural evolution of the iron-oxide supports, correlating to their reducibility. An inverse order of catalytic activity between DP (Au/Fe_OH < Au/Fe_O) and CD (Au/Fe_OH > Au/Fe_O) was observed. Effective gold-support interaction results in a high activity for gold nanoparticles, locally generated by the sintering of dispersed Au atoms on the oxide support in the DP synthesis, while a hydroxylated surface favors the reactivity of externally introduced Au nanoparticles on Fe_OH support for the CD approach. This work reveals why differences in the synthetic protocol translate to differences in the catalytic performance of Au/FeOx catalysts with very similar structural characteristics in CO oxidation.« less

  13. 222 nm Photo-induced radical reactions in silazanes. A combined laser photolysis, EPR, GC-MS and QC Study.

    PubMed

    Knolle, Wolfgang; Wennrich, Luise; Naumov, Sergej; Czihal, Konstanze; Prager, Lutz; Decker, Daniel; Buchmeiser, Michael R

    2010-03-14

    The initiation mechanism of the VUV-induced conversion of polyorganosilazanes into methyl-Si-O-Si networks was studied by means of model disilazane compounds. A combined experimental approach was chosen to determine the primary radicals and their properties (lifetimes, spectra) as well as the major final products. It was verified that both Si-N and Si-CH(3) cleavage occur in the condensed phase, the former with higher yield. The lifetime of the primary Si- and N-centred radicals in de-oxygenated n-hexane solution is less than reaction considerably. In rigid matrix (frozen solutions) CH(3), silyl radicals and methylene radicals CH(2)R are trapped. In the presence of oxygen, peroxyl radicals are formed and serve as precursors of the subsequent oxidative conversion. Product analysis by GC-MS reveals linear R-(Si-O)(n)- chains rather than branched compounds as the initial products of the oxidative conversion of tetramethyldisilazane. It was shown that reactive silylene intermediates do not play a role in the conversion process. Quantum chemical calculations assist in the interpretation.

  14. Constructing Solid-Gas-Interfacial Fenton Reaction over Alkalinized-C3N4 Photocatalyst To Achieve Apparent Quantum Yield of 49% at 420 nm.

    PubMed

    Li, Yunxiang; Ouyang, Shuxin; Xu, Hua; Wang, Xin; Bi, Yingpu; Zhang, Yuanfang; Ye, Jinhua

    2016-10-03

    Efficient generation of active oxygen-related radicals plays an essential role in boosting advanced oxidation process. To promote photocatalytic oxidation for gaseous pollutant over g-C3N4, a solid-gas interfacial Fenton reaction is coupled into alkalinized g-C3N4-based photocatalyst to effectively convert photocatalytic generation of H2O2 into oxygen-related radicals. This system includes light energy as power, alkalinized g-C3N4-based photocatalyst as an in situ and robust H2O2 generator, and surface-decorated Fe(3+) as a trigger of H2O2 conversion, which attains highly efficient and universal activity for photodegradation of volatile organic compounds (VOCs). Taking the photooxidation of isopropanol as model reaction, this system achieves a photoactivity of 2-3 orders of magnitude higher than that of pristine g-C3N4, which corresponds to a high apparent quantum yield of 49% at around 420 nm. In-situ electron spin resonance (ESR) spectroscopy and sacrificial-reagent incorporated photocatalytic characterizations indicate that the notable photoactivity promotion could be ascribed to the collaboration between photocarriers (electrons and holes) and Fenton process to produce abundant and reactive oxygen-related radicals. The strategy of coupling solid-gas interfacial Fenton process into semiconductor-based photocatalysis provides a facile and promising solution to the remediation of air pollution via solar energy.

  15. X-ray induced chemical reaction revealed by in-situ X-ray diffraction and scanning X-ray microscopy in 15 nm resolution (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Ge, Mingyuan; Liu, Wenjun; Bock, David; De Andrade, Vincent; Yan, Hanfei; Huang, Xiaojing; Marschilok, Amy; Takeuchi, Esther; Xin, Huolin; Chu, Yong S.

    2016-09-01

    The detection sensitivity of synchrotron-based X-ray techniques has been largely improved due to the ever increasing source brightness, which have significantly advanced ex-situ and in-situ research for energy materials, such as lithium-ion batteries. However, the strong beam-matter interaction arisen from the high beam flux can significantly modify the material structure. The parasitic beam-induced effect inevitably interferes with the intrinsic material property, which brings difficulties in interpreting experimental results, and therefore requires comprehensive evaluation. Here we present a quantitative in-situ study of the beam-effect on one electrode material Ag2VO2PO4 using four different X-ray probes with different radiation dose rate. The material system we reported exhibits interesting and reversible radiation-induced thermal and chemical reactions, which was further evaluated under electron microscopy to illustrate the underlying mechanism. The work we presented here will provide a guideline in using synchrotron X-rays to distinguish the materials' intrinsic behavior from extrinsic structure changed induced by X-rays, especially in the case of in-situ and operando study where the materials are under external field of either temperature or electric field.

  16. Soft X-ray spectroscopy studies of adsorption and reaction of CO in the presence of H2 over 6 nm MnO nanoparticles supported on mesoporous Co3O4

    NASA Astrophysics Data System (ADS)

    Ralston, Walter T.; Musselwhite, Nathan; Kennedy, Griffin; An, Kwangjin; Horowitz, Yonatan; Cordones, Amy A.; Rude, Bruce; Ahmed, Musahid; Melaet, Gerome; Alayoglu, Selim

    2016-06-01

    MnO nanoparticles (6 nm) were supported on mesoporous spinel Co3O4 and studied using ambient pressure X-ray photoelectron spectroscopy (APXPS) and in situ X-ray absorption spectroscopy (XAS) during hydrogenation of CO. The nature and evolution of surface adsorbed species as well as the oxidation states of the metal oxide surfaces were evaluated under oxidizing, reducing, and H2 + CO (2:1) reaction atmospheres. From APXPS, MnO nanoparticle surfaces were found to be progressively reduced in H2 atmospheres with increasing temperature. Surface adsorbed CO was found to be formed at the expense of lattice O under H2 + CO reaction conditions. In situ XAS indicated that the dominant oxide species were Co(OH)2, Co (II) oxides, MnO, and Mn3O4 under reaction conditions. In situ XAS also indicated the formation of gas phase CO2, the disappearance of lattice O, and the further reduction of Mn3O4 to MnO upon prolonged reaction in H2 + CO. Mass spectroscopy measurements showed the formation of CO2 and hydrocarbons. The spent catalyst was investigated using scanning transmission X-ray microscopy and (scanning) transmission electron microscopy; the catalyst grains were found to be homogeneous.

  17. Destruction of microcystins (cyanotoxins) by UV-254 nm-based direct photolysis and advanced oxidation processes (AOPs): influence of variable amino acids on the degradation kinetics and reaction mechanisms.

    PubMed

    He, Xuexiang; de la Cruz, Armah A; Hiskia, Anastasia; Kaloudis, Triantafyllos; O'Shea, Kevin; Dionysiou, Dionysios D

    2015-05-01

    Hepatotoxic microcystins (MCs) are the most frequently detected group of cyanobacterial toxins. This study investigated the degradation of common MC variants in water, MC-LR, MC-RR, MC-YR and MC-LA, by UV-254 nm-based processes, UV only, UV/H2O2, UV/S2O8(2-) and UV/HSO5(-). Limited direct photolysis of MCs was observed, while the addition of an oxidant significantly improved the degradation efficiency with an order of UV/S2O8(2-) > UV/HSO5(-) > UV/H2O2 at the same initial molar concentration of the oxidant. The removal of MC-LR by UV/H2O2 appeared to be faster than another cyanotoxin, cylindrospermopsin, at either the same initial molar concentration or the same initial organic carbon concentration of the toxin. It suggested a faster reaction of MC-LR with hydroxyl radical, which was further supported by the determined second-order rate constant of MCs with hydroxyl radical. Both isomerization and photohydration byproducts were observed in UV only process for all four MCs; while in UV/H2O2, hydroxylation and diene-Adda double bond cleavage byproducts were detected. The presence of a tyrosine in the structure of MC-YR significantly promoted the formation of monohydroxylation byproduct m/z 1061; while the presence of a second arginine in MC-RR led to the elimination of a guanidine group and the absence of double bond cleavage byproducts. It was therefore demonstrated in this study that the variable amino acids in the structure of MCs influenced not only the degradation kinetics but also the preferable reaction mechanisms.

  18. Sub-10 nm nanopantography

    NASA Astrophysics Data System (ADS)

    Tian, Siyuan; Donnelly, Vincent M.; Ruchhoeft, Paul; Economou, Demetre J.

    2015-11-01

    Nanopantography, a massively parallel nanopatterning method over large areas, was previously shown to be capable of printing 10 nm features in silicon, using an array of 1000 nm-diameter electrostatic lenses, fabricated on the substrate, to focus beamlets of a broad area ion beam on selected regions of the substrate. In the present study, using lens dimensional scaling optimized by computer simulation, and reduction in the ion beam image size and energy dispersion, the resolution of nanopantography was dramatically improved, allowing features as small as 3 nm to be etched into Si.

  19. Albuquerque, NM, USA

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Albuquerque, NM (35.0N, 106.5W) is situated on the edge of the Rio Grande River and flood plain which cuts across the image. The reddish brown surface of the Albuquerque Basin is a fault depression filled with ancient alluvial fan and lake bed sediments. On the slopes of the Manzano Mountains to the east of Albuquerque, juniper and other timber of the Cibola National Forest can be seen as contrasting dark tones of vegetation.

  20. Sub-180 nm generation with borate crystal

    NASA Astrophysics Data System (ADS)

    Qu, Chen; Yoshimura, Masashi; Tsunoda, Jun; Kaneda, Yushi; Imade, Mamoru; Sasaki, Takatomo; Mori, Yusuke

    2014-10-01

    We demonstrated a new scheme for the generation of 179 nm vacuum-ultraviolet (VUV) light with an all-solid-state laser system. It was achieved by mixing the deep-ultraviolet (DUV) of 198.8 nm and the infrared (IR) of 1799.9 nm. While CsB3O5 (CBO) did not satisfy the phase-matching at around 180 nm, 179 nm output was generated with LiB3O5 (LBO) for the first time. The phase-matching property of LBO at around 180 nm was also investigated. There was small deviation from theoretical curve in the measurement, which is still considered reasonable.

  1. 670-nm light treatment reduces complement propagation following retinal degeneration

    PubMed Central

    2012-01-01

    Aim Complement activation is associated with the pathogenesis of age-related macular degeneration (AMD). We aimed to investigate whether 670-nm light treatment reduces the propagation of complement in a light-induced model of atrophic AMD. Methods Sprague–Dawley (SD) rats were pretreated with 9 J/cm2 670-nm light for 3 minutes daily over 5 days; other animals were sham treated. Animals were exposed to white light (1,000 lux) for 24 h, after which animals were kept in dim light (5 lux) for 7 days. Expression of complement genes was assessed by quantitative polymerase chain reaction (qPCR), and immunohistochemistry. Counts were made of C3-expressing monocytes/microglia using in situ hybridization. Photoreceptor death was also assessed using outer nuclear layer (ONL) thickness measurements, and oxidative stress using immunohistochemistry for 4-hydroxynonenal (4-HNE). Results Following light damage, retinas pretreated with 670-nm light had reduced immunoreactivity for the oxidative damage maker 4-HNE in the ONL and outer segments, compared to controls. In conjunction, there was significant reduction in retinal expression of complement genes C1s, C2, C3, C4b, C3aR1, and C5r1 following 670 nm treatment. In situ hybridization, coupled with immunoreactivity for the marker ionized calcium binding adaptor molecule 1 (IBA1), revealed that C3 is expressed by infiltrating microglia/monocytes in subretinal space following light damage, which were significantly reduced in number after 670 nm treatment. Additionally, immunohistochemistry for C3 revealed a decrease in C3 deposition in the ONL following 670 nm treatment. Conclusions Our data indicate that 670-nm light pretreatment reduces lipid peroxidation and complement propagation in the degenerating retina. These findings have relevance to the cellular events of complement activation underling the pathogenesis of AMD, and highlight the potential of 670-nm light as a non-invasive anti-inflammatory therapy. PMID:23181358

  2. Simultaneous three-wavelength continuous wave laser at 946 nm, 1319 nm and 1064 nm in Nd:YAG

    NASA Astrophysics Data System (ADS)

    Lü, Yanfei; Zhao, Lianshui; Zhai, Pei; Xia, Jing; Fu, Xihong; Li, Shutao

    2013-01-01

    A continuous-wave (cw) diode-end-pumped Nd:YAG laser that generates simultaneous laser at the wavelengths 946 nm, 1319 nm and 1064 nm is demonstrated. The optimum oscillation condition for the simultaneous three-wavelength operation has been derived. Using the separation of the three output couplers, we obtained the maximum output powers of 0.24 W at 946 nm, 1.07 W at 1319 nm and 1.88 W at 1064 nm at the absorbed pump power of 11.2 W. A total output power of 3.19 W for the three-wavelength was achieved at the absorbed pump power of 11.2 W with optical conversion efficiency of 28.5%.

  3. New antireflective coatings for 193-nm lithography

    NASA Astrophysics Data System (ADS)

    Xu, Gu; Guerrero, Douglas J.; Dobson, Norman

    1998-06-01

    New bottom antireflective coatings (BARCs) for 193 nm lithography have been recently developed by Brewer Science Inc. Copolymers of benzyl methacrylate (or benzyl acrylate) and hydroxypropyl methacrylate have been synthesized and used as a main component in 193 nm BARCs. The acrylic copolymers have strong absorbance at 193 nm UV light wavelength. The 193 nm BARCs were formulated in safe solvents such as ethyl lactate and formed by spin-on coating process. Thermosetting of the 193 nm BARCs limited their intermixing with photoresists. These 193 nm BARCs had optical density of about 10 micrometers -1, k equals 0.35, and n equals 1.81. Preliminary oxygen plasma etch rates were > 1.5 times DUV resists. Good profiles at small feature sizes (< 0.20 micrometers ) were achieved with tested photoresists.

  4. Pattern transfer processes for 157-nm lithography

    NASA Astrophysics Data System (ADS)

    Miyoshi, Seiro; Furukawa, Takamitsu; Watanabe, Hiroyuki; Irie, Shigeo; Itani, Toshiro

    2002-07-01

    We describe and evaluate three kinds of pattern transfer processes that are suitable for 157-nm lithography. These transfer processes are 1) a hard mask (HM) process using SiO as a HM material, 2) a HM process using an organic bottom anti-reflecting coating (BARC)/SiN structure, and 3) a bi- layer process using a silicon-containing resist and an organic film as the bottom layer. In all of these processes, the underlayer fo the resist acts as an anti-reflecting layer. For the HM processes, we patterned a newly developed fluorine-containing resist using a 157-nm microstepper, and transferred the resist patterns to the hard mask by reactive ion etching (RIE) with minimal critical dimension shift. Using the HM pattern, we then fabricated a 65nm Wsi/poly-Si gate pattern using a high-NA microstepper (NA=0.85). With the bi-layer process, we transferred a 60nm 1:1 lines and spaces pattern of a newly developed silicon-containing resist to a 300nm-thick organic film by RIE. The fabrication of a 65nm 1:1 gate pattern and 60nm 1:1 organic film patten clearly demonstrated that 157-nm lithography is the best candidate for fabricating sub-70nm node devices.

  5. Can DUV take us below 100 nm?

    NASA Astrophysics Data System (ADS)

    Finders, Jo; Jorritsma, Louis; Eurlings, Mark; Moerman, Richard; van Greevenbroek, Henk; van Schoot, Jan B.; Flagello, Donis G.; Socha, Robert J.; Stammler, Thomas

    2001-09-01

    Currently, the 130 nm SIA node is being implemented at leading edge semiconductor manufacturing facilities. Previously, this node appeared to be the insertion point for 193 nm lithography. However, it is evident that for the majority of applications 248 nm will be the wavelength of choice. This once again raises the question how far DUV lithography (248 nm) will take us. To investigate this, overlay, imaging and productivity related issues have to be considered. Although these items become more and more linked at low k1-factors (e.g. overlay and imaging), this paper will focus on some of the imaging related topics.

  6. Lithography strategy for 65-nm node

    NASA Astrophysics Data System (ADS)

    Borodovsky, Yan A.; Schenker, Richard E.; Allen, Gary A.; Tejnil, Edita; Hwang, David H.; Lo, Fu-Chang; Singh, Vivek K.; Gleason, Robert E.; Brandenburg, Joseph E.; Bigwood, Robert M.

    2002-07-01

    Intel will start high volume manufacturing (HVM) of the 65nm node in 2005. Microprocessor density and performance trends will continue to follow Moore's law and cost-effective patterning solutions capable of supporting it have to be found, demonstrated and developed during 2002-2004. Given the uncertainty regarding the readiness and respective capabilities of 157nm and 193nm lithography to support 65nm technology requirements, Intel is developing both lithographic options and corresponding infrastructure with the intent to use both options in manufacturing. Development and use of dual lithographic options for a given technology node in manufacturing is not a new paradigm for Intel: whenever introduction of a new exposure wavelength presented excessive risk to the manufacturing schedule, Intel developed parallel patterning approaches in time for the manufacturing ramp. Both I-line and 248nm patterning solutions were developed and successfully used in manufacturing of the 350nm node at Intel. Similarly, 248nm and 193nm patterning solutions were fully developed for 130nm node high volume manufacturing.

  7. Simultaneous triple 914 nm, 1084 nm, and 1086 nm operation of a diode-pumped Nd:YVO4 laser

    NASA Astrophysics Data System (ADS)

    Lü, Yanfei; Xia, Jing; Liu, Huilong; Pu, Xiaoyun

    2014-10-01

    We report a diode-pumped continuous-wave (cw) triple-wavelength Nd:YVO4 laser operating at 914, 1084, and 1086 nm. A theoretical analysis has been introduced to determine the threshold conditions for simultaneous triple-wavelength laser. Using a T-shaped cavity, we realized an efficient triple-wavelength operation at 4F3/2→4I9/2 and 4F3/2→4I11/2 transitions for Nd:YVO4 crystal, simultaneously. At an absorbed pump power of 16 W (or 25 W of incident pump power), the maximum output power was 2.3 W, which included 914 nm, 1084 nm, and 1086 nm three wavelengths, and the optical conversion efficiency with respect to the absorbed pump power was 14.4%.

  8. Final report on the torque comparison EURAMET.M.T-S2, measurand torque: 10 N.m, 20 N.m, 40 N.m, 60 N.m, 80 N.m, and 100 N.m

    NASA Astrophysics Data System (ADS)

    Röske, Dirk

    2017-01-01

    The purpose of the EURAMET comparison EURAMET.M.T-S2 was to compare the measuring capabilities up to 100 N.m of a reference-type torque calibration machine of ZAG, Slovenia, with the torque standard machine of the Physikalisch-Technische Bundesanstalt (PTB, Braunschweig, Germany) acting as pilot laboratory. A very stable TT1 torque transducer with well-known properties and two torque measuring bridges was used as travelling standard. According to the technical protocol, torque steps of at least 10 N.m, 20 N.m, 40 N.m, 60 N.m, 80 N.m, and 100 N.m had to be measured both in clockwise and anticlockwise directions. For each of the torque steps and both senses of direction of the torque vector, En values were calculated. The results are in general in good agreement with the claimed measurement uncertainties except for the very first measurement at ZAG with additional support and four plate couplings. It seems to be sufficient in a vertical set-up (vertical torque axis) to use only two flexible couplings and there is no need for a further support between the transducers. The measurements with two couplings fulfill the requirement to the En value and support ZAG's claimed uncertainties of measurement. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  9. Sub-70-nm pattern fabrication using an alternating phase-shifting mask in 157-nm lithography

    NASA Astrophysics Data System (ADS)

    Irie, Shigeo; Kanda, Noriyoshi; Watanabe, Kunio; Suganaga, Toshifumi; Itani, Toshiro

    2002-07-01

    In Selete, we have developed various resolution-enhancement technologies (RETs) such as the alternating phase shifting mask (alt-PSM), attenuated-PSM (att-PSM), and off-axis illumination (OAI). The alt-PSM, for example, reduces the k1 factor and extends the lithographic performance. A problem concerning the alt-PSM is the difference in the transmitted light intensities of the non-phase-shifting region and the phase-shifting region which can cause critical-dimension (CD) placement error. The transmitted light intensities of the two regions can be made equal by side-etching, in which the quartz (Qz) is undercut by wet-etching at the side of the transmitting region. We sought to optimize the mask structure in terms of a high numerical aperture (NA) through a simulation using two kinds of structures with a 157 nm exposure wavelength. The structures were a single-trench structure and a dual-trench structure, with each trench dug in the transmitting region. To attain a high NA (NA equals 0.85), we tried to optimize the parameters of the Cr film thickness, the amount of the undercut (side-etching), and the phase shift. The evaluated line pattern sizes were 70 nm (line/space size equals 70/70 nm, 70/140 nm, 70/210 nm, and 70/350 nm) and 50 nm (line/space size equals 50/50 nm, 50/100 nm, 50/150 nm, and 50/250 nm) at the wafer. Further, using the optimized mask, we calculated the lithographic margin of a sub 70 nm pattern through a simulation. For the 70 nm line patterns, we found that it will be difficult to fabricate precisely a 70 nm line patten using a mask with a single- trench structure. And we also found that the most suitable conditions for the dual-trench structure mask were a 90 nm undercut, a 100 nm Cr film thickness, and a 180 degree(s) phase shift. The exposure latitude at a depth of focus (DOF) of 0.3 micrometers , simulated using the optimized mask, was 5.3% for the 70/70 nm pattern, 3.6% for 70/140 nm 16.0% for 70/210 nm, and 29.3% for 70/350 nm. As the pitch

  10. Sub-10 nm nanopantography

    SciTech Connect

    Tian, Siyuan Donnelly, Vincent M. E-mail: economou@uh.edu; Economou, Demetre J. E-mail: economou@uh.edu; Ruchhoeft, Paul

    2015-11-09

    Nanopantography, a massively parallel nanopatterning method over large areas, was previously shown to be capable of printing 10 nm features in silicon, using an array of 1000 nm-diameter electrostatic lenses, fabricated on the substrate, to focus beamlets of a broad area ion beam on selected regions of the substrate. In the present study, using lens dimensional scaling optimized by computer simulation, and reduction in the ion beam image size and energy dispersion, the resolution of nanopantography was dramatically improved, allowing features as small as 3 nm to be etched into Si.

  11. Fabrication of 10nm diameter carbon nanopores

    SciTech Connect

    Radenovic, Aleksandra; Trepagnier, Eliane; Csencsits, Roseann; Downing, Kenneth H; Liphardt, Jan

    2008-09-25

    The addition of carbon to samples, during imaging, presents a barrier to accurate TEM analysis, the controlled deposition of hydrocarbons by a focused electron beam can be a useful technique for local nanometer-scale sculpting of material. Here we use hydrocarbon deposition to form nanopores from larger focused ion beam (FIB) holes in silicon nitride membranes. Using this method, we close 100-200nm diameter holes to diameters of 10nm and below, with deposition rates of 0.6nm per minute. I-V characteristics of electrolytic flow through these nanopores agree quantitatively with a one dimensional model at all examined salt concentrations.

  12. Gallup, NM, CARE Grant Success Story

    EPA Pesticide Factsheets

    A CARE Grant, Level II award, was made to Gallup, NM to focus on cleaning up the waste stream, reuse and recycling of materials, and reclaiming land for these purposes through outreach, education and organization.

  13. Recent progress in 193-nm antireflective coatings

    NASA Astrophysics Data System (ADS)

    Meador, James D.; Guerrero, Douglas J.; Xu, Gu; Shao, Xie; Dobson, Norman; Claypool, James B.; Nowak, Kelly A.

    1999-06-01

    This paper presents the chemistries and properties of organic, spin-on, bottom antireflective coatings (BARCs) that are designed for 193 nm lithography. All of the BARCs are thermosetting and use dye-attached/incorporated polymers. A first generation product, NEXT, will soon be commercialized. NEXT is built form i-line and deep-UV chemistries with the polymeric constituent being a substitute novolac. This product provide outstanding resolution of 0.16 micrometers L/S with several 193 nm photoresists. Second generation chemical platforms under study include acrylics, polyesters, and polyethers with the 193 nm absorbing chromophore being an aromatic function. The performance of selected BARCs from the four platforms is described, including: optical properties, 193 nm litho, plasma etch rates, Prolith modeling data, spin-bowl and waste line compatibility, and ambient stability.

  14. O(D-1) production in ozone photolysis near 310 nm

    NASA Technical Reports Server (NTRS)

    Lin, C.; Demore, W. B.

    1973-01-01

    Relative quantum yields of O(D-1)production, phi, in ozone photolysis from 275 nm to 334 nm were determined in the gas phase at 233 K. The O(D-1) was monitored by means of its reaction with isobutane to form isobutyl alcohol. The light source was a high pressure mercury lamp combined with a monochromator, with a bandwidth of 1.6 nm. The results show a constant phi below 300 nm, which is taken as unity on the basis of previous work. There is a very sharp fall-off in phi which is centered at 308 nm. At 313 nm phi is not greater than 0.1.

  15. Fabrication of sub-10 nm metal nanowire arrays with sub-1 nm critical dimension control

    NASA Astrophysics Data System (ADS)

    Pi, Shuang; Lin, Peng; Xia, Qiangfei

    2016-11-01

    Sub-10 nm metal nanowire arrays are important electrodes for building high density emerging ‘beyond CMOS’ devices. We made Pt nanowire arrays with sub-10 nm feature size using nanoimprint lithography on silicon substrates with 100 nm thick thermal oxide. We further studied the critical dimension (CD) evolution in the fabrication procedure and achieved 0.4 nm CD control, providing a viable solution to the imprint lithography CD challenge as specified by the international technology roadmap for semiconductors. Finally, we fabricated Pt/TiO2/Pt memristor crossbar arrays with the 8 nm electrodes, demonstrating great potential in dimension scaling of this emerging device.

  16. 810nm, 980nm, 1470nm and 1950nm diode laser comparison: a preliminary "ex vivo" study on oral soft tissues

    NASA Astrophysics Data System (ADS)

    Fornaini, Carlo; Merigo, Elisabetta; Sozzi, Michele; Selleri, Stefano; Vescovi, Paolo; Cucinotta, Annamaria

    2015-02-01

    The introduction of diode lasers in dentistry has several advantages, mainly consisting on the reduced size, reduced cost and possibility to beam delivering by optical fibers. At the moment the two diode wavelengths normally utilized in the dental field are 810 and 980 nm for soft tissues treatments. The aim of this study was to compare the efficacy of four different diode wavelengths: 810, 980, 1470 and 1950 nm diode laser for the ablation of soft tissues. Several samples of veal tongue were exposed to the four different wavelengths, at different fluences. The internal temperature of the soft tissues, in the area close to the beam, was monitored with thermocouple during the experiment. The excision quality of the exposed samples have been characterized by means of an optical microscope. Tissue damages and the cut regularity have been evaluated on the base of established criteria. The lowest thermal increase was recorded for 1950 nm laser. Best quality and speed of incision were obtained by the same wavelength. By evaluating epithelial, stromal and vascular damages for all the used wavelengths, the best result, in terms of "tissue respect", have been obtained for 1470 and 1950 nm exposures. From the obtained results 1470 and 1950 nm diode laser showed to be the best performer wavelengths among these used in this "ex vivo" study, probably due to their greatest affinity to water.

  17. Radiation Failures in Intel 14nm Microprocessors

    NASA Technical Reports Server (NTRS)

    Bossev, Dobrin P.; Duncan, Adam R.; Gadlage, Matthew J.; Roach, Austin H.; Kay, Matthew J.; Szabo, Carl; Berger, Tammy J.; York, Darin A.; Williams, Aaron; LaBel, K.; Ingalls, James D.

    2016-01-01

    In this study the 14 nm Intel Broadwell 5th generation core series 5005U-i3 and 5200U-i5 was mounted on Dell Inspiron laptops, MSI Cubi and Gigabyte Brix barebones and tested with Windows 8 and CentOS7 at idle. Heavy-ion-induced hard- and catastrophic failures do not appear to be related to the Intel 14nm Tri-Gate FinFET process. They originate from a small (9 m 140 m) area on the 32nm planar PCH die (not the CPU) as initially speculated. The hard failures seem to be due to a SEE but the exact physical mechanism has yet to be identified. Some possibilities include latch-ups, charge ion trapping or implantation, ion channels, or a combination of those (in biased conditions). The mechanism of the catastrophic failures seems related to the presence of electric power (1.05V core voltage). The 1064 nm laser mimics ionization radiation and induces soft- and hard failures as a direct result of electron-hole pair production, not heat. The 14nm FinFET processes continue to look promising for space radiation environments.

  18. Diode laser (980nm) cartilage reshaping

    NASA Astrophysics Data System (ADS)

    El Kharbotly, A.; El Tayeb, T.; Mostafa, Y.; Hesham, I.

    2011-03-01

    Loss of facial or ear cartilage due to trauma or surgery is a major challenge to the otolaryngologists and plastic surgeons as the complicated geometric contours are difficult to be animated. Diode laser (980 nm) has been proven effective in reshaping and maintaining the new geometric shape achieved by laser. This study focused on determining the optimum laser parameters needed for cartilage reshaping with a controlled water cooling system. Harvested animal cartilages were angulated with different degrees and irradiated with different diode laser powers (980nm, 4x8mm spot size). The cartilage specimens were maintained in a deformation angle for two hours after irradiation then released for another two hours. They were serially measured and photographed. High-power Diode laser irradiation with water cooling is a cheep and effective method for reshaping the cartilage needed for reconstruction of difficult situations in otorhinolaryngologic surgery. Key words: cartilage,diode laser (980nm), reshaping.

  19. Stochastic effects in 11 nm imaging of extreme ultraviolet lithography with chemically amplified resists

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro; Santillan, Julius Joseph; Itani, Toshiro

    2014-03-01

    The resolution of extreme ultraviolet (EUV) lithography with chemically amplified resist processes has reached 16 nm (half-pitch). The development of chemically amplified resists is ongoing toward the 11 nm node. However, the stochastic effects are increasingly becoming a significant concern with the continuing shrinkage of features. In this study, the fluctuation of protected unit distribution caused by the stochastic effects during image formation was investigated assuming line-and-space patterns with 11 nm half-pitch. Contrary to expectations, the standard deviation of the number of protected units connected to a polymer after postexposure baking (PEB) did not differ from that for 16 nm half-pitch. The standard deviation after PEB increased with the effective reaction radius for deprotection and the initial standard deviation before PEB. Because of the severe requirements for resist processes, the stochastic effects in chemical reactions should be taken into account in the design of next-generation resists.

  20. 14nm M1 triple patterning

    NASA Astrophysics Data System (ADS)

    Li, Qiao; Ghosh, Pradiptya; Abercrombie, David; LaCour, Pat; Kanodia, Suniti

    2012-03-01

    With 20nm production becoming a reality, research has started to focus on the technology needs for 14nm. The LELE double patterning used in 20nm production will not be able to resolve M1 for 14nm. Main competing enabling technologies for the 14nm M1 are SADP, EUV, and LELELE (referred as LE3 thereafter) triple patterning. SADP has a number of concerns of 1. density, as a layout geometry needs to stay complete as a whole, and can not be broken; 2. the complexity in SADP mask generation and debug feedback to designers; 3. the subtraction nature of the trim mask further complicates OPC and yield. While EUV does not share those concerns, it faces significant challenges on the manufacturing equipment side. Of the SADP concerns, LE3 only shares that of complexity involved in mask generation and intuitive debug feedback mechanism. It does not require a layout geometry to stay as a whole, and it benefits from the affinity to LELE which is being deployed for 20nm production. From a process point of view, this benefit from affinity to LELE is tremendous due to the data and knowledge that have been collected and will be coming from the LELE deployment. In this paper, we first recount the computational complexity of the 3-colorability problem which is an integral part of a LE3 solution. We then describe graph characteristics that can be exploited such that 3-colorability is equivalent under divide-and-conquer. Also outlined are heuristics, which are generally applied in solving computationally intractable problems, for the 3-colorability problem, and the importance in choosing appropriate worst-case exponential runtime algorithms. This paper concludes with a discussion on the new hierarchical problem that faces 3-colorability but not 2-colorability and proposals for non-3-colorability feedback mechanism.

  1. Comparative study of Nd:KGW lasers pumped at 808 nm and 877 nm

    NASA Astrophysics Data System (ADS)

    Huang, Ke; Ge, Wen-Qi; Zhao, Tian-Zhuo; He, Jian-Guo; Feng, Chen-Yong; Fan, Zhong-Wei

    2015-10-01

    The laser performance and thermal analysis of Nd:KGW laser continuously pumped by 808 nm and 877 nm are comparatively investigated. Output power of 670 mW and 1587 mW, with nearly TEM00 mode, are achieved respectively at 808 nm pump and 877 nm pump. Meanwhile, a high-power passively Q-switched Nd:KGW/Cr4+:YAG laser pumped at 877 nm is demonstrated. An average output power of 1495 mW is obtained at pump power of 5.22 W while the laser is operating at repetition of 53.17 kHz. We demonstrate that 877 nm diode laser is a more potential pump source for Nd:KGW lasers.

  2. Synthesis of fluorinated materials for 193-nm immersion lithography and 157-nm lithography

    NASA Astrophysics Data System (ADS)

    Yamashita, T.; Ishikawa, T.; Yoshida, T.; Hayamai, T.; Araki, Takayuki; Aoyama, H.; Hagiwara, T.; Itani, Toshiro; Fujii, Kiyoshi

    2005-05-01

    Various fluorinated polymers were synthesized for application in 193-nm immersion lithography with the goal of improving 157-nm photoresist performance. Their fundamental properties were characterized, such as transparency at 193-nm and 157-nm (wavelength) and solubility in water and a standard alkaline developer. High transparency, i.e., absorbance better than 0.3 μm-1 at 193-nm wavelength, was achieved. The dissolution behaviors of them were studied by using the Quartz Crystal Microbalance (QCM) method. We find that the dissolution rate of Poly(norbornene-2-fluoro-2-hexafluoroalchol) (PNB1FVIP) in 0.065N tetramethylammonium hydroxide (TMAH) was >200 times (nm/s) faster than that of the copolymer of tetrafluoroethylene (TFE) and norbornene-2-fluoro-2-hexafluoroalchol (TFE/NB1FVIP). A resist based on TFE/NB1FVIP was able to delineate 75 nm dense lines by exposure at 193-nm (wavelength) with an alternating phase shift mask using a 0.75 NA ArF scanner. The dissolution rates of the fluoropolymers in water and a 0.262N and 0.065 TMAH can be controlled by optimizing counter monomers containing hexafluoroisopropanol (HFA) unit, carboxylic acid unit and so on. In addition, we have collect water contact angle data. This data shows that fluoropolymers can be used as resist cover materials for 193-nm immersion lithography.

  3. White Sands, Carrizozo Lava Beds, NM

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A truly remarkable view of White Sands and the nearby Carrizozo Lava Beds in southeast NM (33.5N, 106.5W). White Sands, site of the WW II atomic bomb development and testing facility and later post war nuclear weapons testing that can still be seen in the cleared circular patterns on the ground.

  4. Radiation Tolerance of 65nm CMOS Transistors

    DOE PAGES

    Krohn, M.; Bentele, B.; Christian, D. C.; ...

    2015-12-11

    We report on the effects of ionizing radiation on 65 nm CMOS transistors held at approximately -20°C during irradiation. The pattern of damage observed after a total dose of 1 Grad is similar to damage reported in room temperature exposures, but we observe less damage than was observed at room temperature.

  5. The 503nm pigment of Escherichia coli

    PubMed Central

    Kamitakahara, Joyce R.; Polglase, W. J.

    1970-01-01

    The yield of cell protein was one-third less for streptomycin-dependent Escherichia coli B than for the wild-type parent strain when both were grown aerobically on a medium with limiting glucose, but anaerobically the yield of protein was similar for both strains. The transient pigment absorbing at 503nm that is known to be present in E. coli and other organisms was not detectable in streptomycin-dependent mutants nor in a non-dependent (energy-deficient) revertant. When wild-type E. coli B was grown on limiting glucose–salts medium containing 2,4 dinitrophenol, the yield of cell protein was decreased and formation of the 503nm pigment was inhibited. Fumarase, aconitase and glucose 6-phosphate dehydrogenase were de-repressed in E. coli B cells grown with excess of glucose in a medium containing 2,4-dinitrophenol. In air-oxidized, wild-type E. coli B cells, the 503nm pigment appeared before reduced cytochromes when gluconate was the substrate but failed to appear when succinate was the substrate. The results provide evidence for a role of the 503nm pigment in aerobic energy metabolism, possibly as an electron acceptor from NADPH. PMID:4395501

  6. VizieR Online Data Catalog: Thorium spectrum from 250nm to 5500nm (Redman+, 2014)

    NASA Astrophysics Data System (ADS)

    Redman, S. L.; Nave, G.; Sansonetti, C. J.

    2014-04-01

    We observed the spectrum of a commercial sealed Th/Ar HCL running at 25mA for almost 15hr starting on 2011 November 2. The region of observation was limited to between 8500/cm and 28000/cm (360nm and 1200nm) by the sensitivity of the silicon photodiode detector. (5 data files).

  7. Efficient 1645-nm Er:YAG laser

    NASA Astrophysics Data System (ADS)

    Young, York E.; Setzler, Scott D.; Snell, Kevin J.; Budni, Peter A.; Pollak, Thomas M.; Chicklis, E. P.

    2004-05-01

    We report a resonantly fiber-laser-pumped Er:YAG laser operating at the eye-safe wavelength of 1645 nm, exhibiting 43% optical efficiency and 54% incident slope efficiency and emitting 7-W average power when repetitively Q switched at 10 kHz. To our knowledge, this is the best performance (conversion efficiency and average power) obtained from a bulk solid-state Q-switched erbium laser. At a 1.1-kHz pulse repetition frequency the laser produces 3.4-mJ pulses with a corresponding peak power of 162 kW. Frequency doubling to produce 822.5-nm, 4.7-kW pulses at 10 kHz was performed to demonstrate the laser's utility.

  8. DNA Charge Transport over 34 nm

    PubMed Central

    Slinker, Jason D.; Muren, Natalie B.; Renfrew, Sara E.; Barton, Jacqueline K.

    2011-01-01

    Molecular wires show promise in nanoscale electronics but the synthesis of uniform, long conductive molecules is a significant challenge. DNA of precise length, by contrast, is easily synthesized, but its conductivity has not been explored over the distances required for nanoscale devices. Here we demonstrate DNA charge transport (CT) over 34 nm in 100-mer monolayers on gold. Multiplexed gold electrodes modified with 100-mer DNA yield sizable electrochemical signals from a distal, covalent Nile Blue redox probe. Significant signal attenuation upon incorporation of a single base pair mismatch demonstrates that CT is DNA-mediated. Efficient cleavage of these 100-mers by a restriction enzyme indicates that the DNA adopts a native conformation that is accessible to protein binding. Similar electron transfer rates are measured through 100-mer and 17-mer monolayers, consistent with rate-limiting electron tunneling through the saturated carbon linker. This DNA-mediated CT distance of 34 nm surpasses most reports of molecular wires. PMID:21336329

  9. Radiation Status of Sub-65 nm Electronics

    NASA Technical Reports Server (NTRS)

    Pellish, Jonathan A.

    2011-01-01

    Ultra-scaled complementary metal oxide semiconductor (CMOS) includes commercial foundry capabilities at and below the 65 nm technology node Radiation evaluations take place using standard products and test characterization vehicles (memories, logic/latch chains, etc.) NEPP focus is two-fold: (1) Conduct early radiation evaluations to ascertain viability for future NASA missions (i.e. leverage commercial technology development). (2) Uncover gaps in current testing methodologies and mechanism comprehension -- early risk mitigation.

  10. Binary 193nm photomasks aging phenomenon study

    NASA Astrophysics Data System (ADS)

    Dufaye, Félix; Sartelli, Luca; Pogliani, Carlo; Gough, Stuart; Sundermann, Frank; Miyashita, Hiroyuki; Hidenori, Yoshioka; Charras, Nathalie; Brochard, Christophe; Thivolle, Nicolas

    2011-05-01

    193nm binary photomasks are still used in the semiconductor industry for the lithography of some critical layers for the nodes 90nm and 65nm, with high volumes and over long period. These 193nm binary masks seem to be well-known but recent studies have shown surprising degrading effects, like Electric Field induced chromium Migration (EFM) [1] or chromium migration [2] [3] . Phase shift Masks (PSM) or Opaque MoSi On Glass (OMOG) might not be concerned by these effects [4] [6] under certain conditions. In this paper, we will focus our study on two layers gate and metal lines. We will detail the effects of mask aging, with SEM top view pictures revealing a degraded chromium edge profile and TEM chemical analyses demonstrating the growth of a chromium oxide on the sidewall. SEMCD measurements after volume production indicated a modified CD with respect to initial CD data after manufacture. A regression analysis of these CD measurements shows a radial effect, a die effect and an isolated-dense effect. Mask cleaning effectiveness has also been investigated, with sulphate or ozone cleans, to recover the mask quality in terms of CD. In complement, wafer intrafield CD measurements have been performed on the most sensitive structure to monitor the evolution of the aging effect on mask CD uniformity. Mask CD drift have been correlated with exposure dose drift and isolated-dense bias CD drift on wafers. In the end, we will try to propose a physical explanation of this aging phenomenon and a solution to prevent from it occurring.

  11. Laser damage database at 1064 nm

    SciTech Connect

    Rainer, F.; Gonzales, R.P.; Morgan, A.J.

    1990-03-01

    In conjunction with our diversification of laser damage testing capabilities, we have expanded upon a database of threshold measurements and parameter variations at 1064 nm. This includes all tests at low pulse-repetition frequencies (PRF) ranging from single shots to 120 Hz. These tests were conducted on the Reptile laser facility since 1987 and the Variable Pulse Laser (VPL) facility since 1988. Pulse durations ranged from 1 to 16 ns. 10 refs., 14 figs.

  12. 3 Watt CW OPO tunable 604nm to 616nm for quantum optics applications

    NASA Astrophysics Data System (ADS)

    Henderson, Angus; Halfmann, Thomas; Mieth, Simon

    2012-06-01

    A continuous wave optical parametric oscillator (CW OPO) pumped by a fiber laser has been developed which emits up to 3 Watts of single longitudinal mode radiation tunable in the wavelength range 604nm to 616nm. The device is a modified version of the ``Argos'' Model 2400 commercial product by Lockheed Martin Aculight. A 15 Watt 1064nm fiber laser pumps a CW OPO based upon periodically-poled Lithium Niobate (PPLN). A short section of the nonlinear crystal is poled to allow efficient intracavity sum frequency generation (SFG) between the OPO pump and signal wavelengths to generate orange radiation. The device can be coarsely tuned by matching the poling periods and temperature within the nonlinear crystal to phase-match both OPO and SFG processes simultaneously. Fine mode-hop-free tuning of the orange wavelength of up to 100GHz range can be achieved by applying a voltage to a PZT which tunes the pump laser. By similar intracavity conversion schemes, the system offers the potential of providing high power at wavelengths from 600nm to 1400nm in addition to the direct signal and idler wavelength ranges from 1400nm to 4630nm. Such capability comes without the complexity and reliability issues which are inherent in dye and Ti:Sapphire systems. Details of the OPO system performance and its use in quantum optics applications will be provided.

  13. 635nm diode laser biostimulation on cutaneous wounds

    NASA Astrophysics Data System (ADS)

    Solmaz, Hakan; Gülsoy, Murat; Ülgen, Yekta

    2014-05-01

    Biostimulation is still a controversial subject in wound healing studies. The effect of laser depends of not only laser parameters applied but also the physiological state of the target tissue. The aim of this project is to investigate the biostimulation effects of 635nm laser irradiation on the healing processes of cutaneous wounds by means of morphological and histological examinations. 3-4 months old male Wistar Albino rats weighing 330 to 350 gr were used throughout this study. Low-level laser therapy was applied through local irradiation of red light on open skin excision wounds of 5mm in diameter prepared via punch biopsy. Each animal had three identical wounds on their right dorsal part, at which two of them were irradiated with continuous diode laser of 635nm in wavelength, 30mW of power output and two different energy densities of 1 J/cm2 and 3 J/cm2. The third wound was kept as control group and had no irradiation. In order to find out the biostimulation consequences during each step of wound healing, which are inflammation, proliferation and remodeling, wound tissues removed at days 3, 7, 10 and 14 following the laser irradiation are morphologically examined and than prepared for histological examination. Fragments of skin including the margin and neighboring healthy tissue were embedded in paraffin and 6 to 9 um thick sections cut are stained with hematoxylin and eosin. Histological examinations show that 635nm laser irradiation accelerated the healing process of cutaneous wounds while considering the changes of tissue morphology, inflammatory reaction, proliferation of newly formed fibroblasts and formation and deposition of collagen fibers. The data obtained gives rise to examine the effects of two distinct power densities of low-level laser irradiation and compare both with the non-treatment groups at different stages of healing process.

  14. Relationship between sensitizer concentration and resist performance of chemically amplified extreme ultraviolet resists in sub-10 nm half-pitch resolution region

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro; Santillan, Julius Joseph; Itani, Toshiro

    2017-01-01

    The development of lithography processes with sub-10 nm resolution is challenging. Stochastic phenomena such as line width roughness (LWR) are significant problems. In this study, the feasibility of sub-10 nm fabrication using chemically amplified extreme ultraviolet resists with photodecomposable quenchers was investigated from the viewpoint of the suppression of LWR. The relationship between sensitizer concentration (the sum of acid generator and photodecomposable quencher concentrations) and resist performance was clarified, using the simulation based on the sensitization and reaction mechanisms of chemically amplified resists. For the total sensitizer concentration of 0.5 nm-3 and the effective reaction radius for the deprotection of 0.1 nm, the reachable half-pitch while maintaining 10% critical dimension (CD) LWR was 11 nm. The reachable half-pitch was 7 nm for 20% CD LWR. The increase in the effective reaction radius is required to realize the sub-10 nm fabrication with 10% CD LWR.

  15. Drug Reactions

    MedlinePlus

    Most of the time, medicines make our lives better. They reduce aches and pains, fight infections, and control problems such as high blood pressure or diabetes. But medicines can also cause unwanted reactions. One problem is ...

  16. 75 FR 81437 - Amendment of Class E Airspace; Taos, NM

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-28

    ... Taos, NM. Decommissioning of the Ski non-directional beacon (NDB) at Taos Regional Airport, Taos, NM... Taos, NM area. Decommissioning of the Ski NDB and cancellation of the NDB approach at Taos...

  17. Deep ultraviolet (254 nm) focal plane array

    NASA Astrophysics Data System (ADS)

    Cicek, Erdem; Vashaei, Zahra; McClintock, Ryan; Razeghi, Manijeh

    2011-10-01

    We report the synthesis, fabrication and testing of a 320 × 256 focal plane array (FPA) of back-illuminated, solarblind, p-i-n, AlxGa1-xN-based detectors, fully realized within our research laboratory. We implemented a novel pulsed atomic layer deposition technique for the metalorganic chemical vapor deposition (MOCVD) growth of crackfree, thick, and high Al composition AlxGa1-xN layers. Following the growth, the wafer was processed into a 320 × 256 array of 25 μm × 25 μm pixels on a 30 μm pixel-pitch and surrounding mini-arrays. A diagnostic mini-array was hybridized to a silicon fan-out chip to allow the study of electrical and optical characteristics of discrete pixels of the FPA. At a reverse bias of 1 V, an average photodetector exhibited a low dark current density of 1.12×10-8 A/cm2. Solar-blind operation is observed throughout the array with peak detection occurring at wavelengths of 256 nm and lower and falling off three orders of magnitude by 285 nm. After indium bump deposition and dicing, the FPA is hybridized to a matching ISC 9809 readout integrated circuit (ROIC). By developing a novel masking technology, we significantly reduced the visible response of the ROIC and thus the need for external filtering to achieve solar- and visible-blind operation is eliminated. This allowed the FPA to achieve high external quantum efficiency (EQE): at 254 nm, average pixels showed unbiased peak responsivity of 75 mA/W, which corresponds to an EQE of ~37%. Finally, the uniformity of the FPA and imaging properties are investigated.

  18. Laser-induced bulk damage of silica glass at 355nm and 266nm

    NASA Astrophysics Data System (ADS)

    Kashiwagi, R.; Aramomi, S.

    2016-12-01

    Laser processing machines using Nd:YAG 3rd harmonic wave (355 nm) and 4th harmonic wave (266 nm) have been developed and put into practical use lately. Due to this, optical elements with high laser durability to 355 nm and 266 nm are required. Silica glass is the optical element which has high UV transmission and high laser durability. Laser-induced surface damage of the silica glass has been studied in detail, but we hardly have the significant knowledge of laserinduced bulk damage. This knowledge is required in order to evaluate the silica glass itself. That is because cracks and scratches on the surface give rise to a higher possibility of damage. Therefore, we studied the laser durability of a variety of the silica glass samples by 1-on-1 and S-on-1 laser-induced bulk damage threshold (LIDT) at 355 nm and 266 nm. In this study, we gained knowledge in three areas about bulk damage to the silica glass. First, the LIDT became lower as shot counts increased. Second, the LIDT decreased as the hydroxyl content in the silica glass increased. Last, the LIDT became higher as the hydrogen concentration in the silica glass increased. Under the UV irradiation, impurities are generated and the silica glass absorbs more light. Therefore, the LIDT decreased as shot counts increased. Also, the hydroxyl in particular generates more impurities, so damage easily occurs. On the other hand, the hydrogen reacts with impurities and absorption is suppressed. Based on these results, we can improve laser durability at 355 nm and 266 nm by reducing the hydroxyl content and increasing the hydrogen concentration in the silica glass.

  19. Yb fiber amplifier at 972.5 nm with frequency quadrupling to 243.1 nm

    NASA Astrophysics Data System (ADS)

    Burkley, Z.; Rasor, C.; Cooper, S. F.; Brandt, A. D.; Yost, D. C.

    2017-01-01

    We demonstrate a continuous-wave ytterbium-doped fiber amplifier which produces 6.3 W at a wavelength of 972.5 nm. We frequency-quadruple this source in two resonant doubling stages to generate 530 mW at 243.1 nm. Radiation at this wavelength is required to excite the 1S-2S transition in atomic hydrogen and could therefore find application in experimental studies of hydrogen and anti-hydrogen.

  20. 248nm silicon photoablation: Microstructuring basics

    NASA Astrophysics Data System (ADS)

    Poopalan, P.; Najamudin, S. H.; Wahab, Y.; Mazalan, M.

    2015-05-01

    248nm pulses from a KrF excimer laser was used to ablate a Si wafer in order to ascertain the laser pulse and energy effects for use as a microstructuring tool for MEMS fabrication. The laser pulses were varied between two different energy levels of 8mJ and 4mJ while the number of pulses for ablation was varied. The corresponding ablated depths were found to range between 11 µm and 49 µm, depending on the demagnified beam fluence.

  1. Photolysis of formic acid at 355 nm

    NASA Astrophysics Data System (ADS)

    Martinez, Denhi; Bautista, Teonanacatl; Guerrero, Alfonso; Alvarez, Ignacio; Cisneros, Carmen

    2015-05-01

    Formic acid is well known as a food additive and recently an application on fuel cell technology has emerged. In this work we have studied the dissociative ionization process by multiphoton absorption of formic acid molecules at 355nm wavelength photons, using TOF spectrometry in reflectron mode (R-TOF). Some of the most abundant ionic fragments produced are studied at different settings of the laser harmonic generator. The dependence of the products on these conditions is reported. This work was supported by CONACYT Project 165410 and PAPIIT IN102613 and IN101215.

  2. 248nm silicon photoablation: Microstructuring basics

    SciTech Connect

    Poopalan, P.; Najamudin, S. H.; Wahab, Y.; Mazalan, M.

    2015-05-15

    248nm pulses from a KrF excimer laser was used to ablate a Si wafer in order to ascertain the laser pulse and energy effects for use as a microstructuring tool for MEMS fabrication. The laser pulses were varied between two different energy levels of 8mJ and 4mJ while the number of pulses for ablation was varied. The corresponding ablated depths were found to range between 11 µm and 49 µm, depending on the demagnified beam fluence.

  3. Nonlinear absorption properties of DKDP crystal at 263 nm and 351 nm

    NASA Astrophysics Data System (ADS)

    Chai, Xiangxu; Zhu, Qihua; Feng, Bin; Li, Fuquan; Feng, Xi; Wang, Fang; Han, Wei; Wang, Liquan

    2017-02-01

    At the wavelength of 263 nm and 351 nm, the nonlinear absorption curves of 66% deuterated DKDP crystal were measured in the geometries of beam polarizing along the optics axis (E∥Z) and perpendicular to it (E⊥Z). The results indicate that the nonlinear absorption in the E⊥Z geometry is stronger than that in the E∥Z geometry. The nonlinear absorptions at 263 nm and 351 nm are identified to two- and three-photon absorption, respectively. The theoretical fits to the experimental data yields the two-photon absorption coefficients of 0.32 ± 0.03 cm/GW (E⊥Z geometry) and 0.17 ± 0.02 cm/GW (E∥Z geometry) at 263 nm, and the three-photon absorption coefficients of (8.1 ± 1.1) × 10-4 cm3/GW2 (E⊥Z geometry) and (2.2 ± 0.5) × 10-4 cm3/GW2 (E∥Z geometry) at 351 nm.

  4. DNA charge transport over 34 nm

    NASA Astrophysics Data System (ADS)

    Slinker, Jason D.; Muren, Natalie B.; Renfrew, Sara E.; Barton, Jacqueline K.

    2011-03-01

    Molecular wires show promise in nanoscale electronics, but the synthesis of uniform, long conductive molecules is a significant challenge. Deoxyribonucleic acid (DNA) of precise length, by contrast, is synthesized easily, but its conductivity over the distances required for nanoscale devices has not been explored. Here we demonstrate DNA charge transport (CT) over 34 nm in 100-mer monolayers on gold. Multiplexed gold electrodes modified with 100-mer DNA yield sizable electrochemical signals from a distal, covalent Nile Blue redox probe. Significant signal attenuation upon incorporation of a single base-pair mismatch demonstrates that CT is DNA-mediated. Efficient cleavage of these 100-mers by a restriction enzyme indicates that the DNA adopts a native conformation accessible to protein binding. Similar electron-transfer rates measured through 100-mer and 17-mer monolayers are consistent with rate-limiting electron tunnelling through the saturated carbon linker. This DNA-mediated CT distance of 34 nm surpasses that of most reports of molecular wires.

  5. Low-intensity LED (625 and 405 nm) and laser (805 nm) killing of Propionibacterium acnes and Staphylococcus epidermidis

    NASA Astrophysics Data System (ADS)

    Tuchina, Elena S.; Tuchin, Valery V.

    2009-02-01

    In the present work we have investigated in vitro sensitivity of microorganisms P. acnes and S. epidermidis to action of red (625 nm and 405 nm) and infrared (805 nm) radiations in combination with photosensitizes Methylene Blue and Indocyanine Green.

  6. SITS Derivatization of Peptides to Enhance 266 nm Ultraviolet Photodissociation (UVPD)

    NASA Astrophysics Data System (ADS)

    Quick, M. Montana; Mehaffey, M. Rachel; Johns, Robert W.; Parker, W. Ryan; Brodbelt, Jennifer S.

    2017-03-01

    N-terminal derivatization of peptides with the chromogenic reagent 4-acetamido-4-isothiocyanatostilbene-2,2-disulfonic acid (SITS) is demonstrated to enhance the efficiency of 266 nm ultraviolet photodissociation (UVPD). Attachment of the chromophore results in a mass shift of 454 Da and provides significant gains in the number and abundances of diagnostic fragment ions upon UVPD. Activation of SITS-tagged peptides with 266 nm UVPD leads to many fragment ions akin to the a/b/y ions commonly produced by CID, along with other sequence ions (c, x, and z) typically accessed through higher energy pathways. Extreme bias towards C-terminal fragment ions is observed upon activation of SITS-tagged peptides using multiple 266 nm laser pulses. Due to the high reaction efficiency of the isothiocyanate coupling to the N-terminus of peptides, we demonstrate the ability to adapt this strategy to a high-throughput LC-MS/MS workflow with 266 nm UVPD.

  7. TCSPC FLIM in the wavelength range from 800 nm to 1700 nm (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Becker, Wolfgang; Shcheslavsky, Vladislav

    2016-03-01

    Excitation and detection in the wavelength range above 800nm is a convenient and relatively inexpensive way to increase the penetration depth in optical microscopy. Moreover, detection at long wavelength avoids the problem that tissue autofluorescence contaminates the signals from endogenous fluorescence probes. FLIM at NIR wavelength may therefore be complementary to multiphoton microscopy, especially if the lifetimes of NIR fluorophores report biological parameters of the tissue structures they are bound to. Unfortunately, neither the excitation sources nor the detectors of standard confocal and multiphoton laser scanning systems are directly suitable for excitation and detection of NIR fluorescence. Most of these problems can be solved, however, by using ps diode lasers or Ti:Sapphire lasers at their fundamental wavelength, and NIR-sensitive detectors. With NIR-sensitive PMTs the detection wavelength range can be extended up to 900 nm, with InGaAs SPAD detectors up to 1700 nm. Here, we demonstrate the use of a combination of laser scanning, multi-dimensional TCSPC, and advanced excitation sources and detectors for FLIM at up to 1700 nm. The performance was tested at tissue samples incubated with NIR dyes. The fluorescence lifetimes generally get shorter with increasing absorption and emission wavelengths of the dyes. For the cyanine dye IR1061, absorbing around 1060 nm, the lifetime was found to be as short as 70 ps. Nevertheless the fluorescence decay could still be clearly detected. Almost all dyes showed clear lifetime changes depending on the binding to different tissue constituents.

  8. Comparison of 980-nm and 1070-nm in endovenous laser treatment (EVLT)

    NASA Astrophysics Data System (ADS)

    Topaloglu, Nermin; Tabakoglu, Ozgur; Ergenoglu, Mehmet U.; Gülsoy, Murat

    2009-07-01

    The use of endovenous laser treatment for varicose veins has been increasing in recent years. It is a safer technique than surgical vein stripping. Its complications (e.g. bruising, pain) are less than the complications of surgical vein stripping. But best parameters such as optimum wavelength, power, and application duration are still under investigation to clarify uncertainties about this technique. To prevent its complications and improve its clinical outcomes, the exact mechanism of it has to be known. The aim of this study is to investigate the effect of different laser wavelengths on endovenous laser therapy. In this study 980-nm diode laser and 1070-nm fiber laser were used. Human veins were irradiated with 980-nm and 1070-nm lasers at 8 W and 10 W to find the optimal power and wavelength. After laser application, remarkable shrinkage was observed. Inner and outer diameters of the veins also narrowed for both of the laser types. 10 W of 980-nm laser application led to better shrinkage results.

  9. Dual illumination OCT at 1050nm and 840nm for whole eye segment imaging

    NASA Astrophysics Data System (ADS)

    Fan, Shanhui; Qin, Lin; Dai, Cuixia; Zhou, Chuanqing

    2014-11-01

    We presented an improved dual channel dual focus spectral domain optical coherence tomography (SD-OCT) with two illuminations at 840 nm and 1050 nm for whole eye segment imaging and biometry in vivo. The two light beams were coupled and optically optimized to scan the anterior and posterior segment of the eye simultaneously. This configuration with dichroic mirrors integrated in the sample arm enables us to acquire images from the anterior segment and retina effectively with minimum loss of sample signal. In addition, the full resolved complex (FRC) method was applied to double the imaging depth for the whole anterior segment imaging by eliminating the mirror image. The axial resolution for 1050 nm and 840 nm OCT was 14 μm and 8 μm in air, respectively. Finally, the system was successfully tested in imaging the unaccommodated and accommodated eyes. The preliminary results demonstrated the significant improvements comparing with our previous dual channel SD-OCT configuration in which the two probing beams had the same central wavelength of 840 nm.

  10. 308-nm excimer laser in endodontics

    NASA Astrophysics Data System (ADS)

    Liesenhoff, Tim

    1992-06-01

    Root canal preparation was performed on 20 extracted human teeth. After opening the coronal pulp, the root canals were prepared by 308 nm excimer laser only. All root canals were investigated under SEM after separation in the axial direction. By sagittal separation of the mandibles of freshly slaughtered cows, it was possible to get access to the tissues and irradiate under optical control. Under irradiation of excimer laser light, tissue starts to fluoresce. It was possible to demonstrate that each tissue (dentin, enamel, bone, pulpal, and connective tissue) has a characteristic spectral pattern. The SEM analyses showed that it is well possible to prepare root canals safely. All organic soft tissue has been removed by excimer laser irradiation. There was no case of via falsa. The simultaneous spectroscopic identification of the irradiated tissue provides a safe protection from overinstrumentation. First clinical trials on 20 patients suffering of chronical apical parodontitis have been carried out successfully.

  11. Microscope illumination systems for 157 nm

    NASA Astrophysics Data System (ADS)

    Pesch, Alexander; Uhlendorf, Kristina; Deparnay, Arnaud; Erdmann, Lars; Kuschnerus, Peter; Engel, Thomas; Brunner, Robert

    2003-05-01

    The image quality of an inspection microscope depends strongly on the performance of the illumination system. Especially in the case of laser-based illumination it is necessary to transform the original beam profile into a homogeneous light spot with a flat top field distribution. Simultaneously, speckles caused by the coherence of the laser have to be reduced. Here we discuss different ways to homogenize the multi mode beam profile of a pulsed compact 157 nm excimer laser. A variety of setups, combining dynamic acting diffusers, microlens arrays and primary lenses were realized and characterized in several geometrical arrangements. The homogenizers were evaluated and characterized especially with respect to the statistical behavior on the integrated pulse number.

  12. Allergic Reactions

    MedlinePlus

    ... that is right for you. In many instances, allergy immunotherapy in the form of shots or tablets is an effective, cost-efficient long term treatment approach. While there is not yet ... Healthy Tips • Allergy symptoms are the result of a chain reaction ...

  13. Measurement of 100 nm and 60 nm Particle Standards by Differential Mobility Analysis

    PubMed Central

    Mulholland, George W.; Donnelly, Michelle K.; Hagwood, Charles R.; Kukuck, Scott R.; Hackley, Vincent A.; Pui, David Y. H.

    2006-01-01

    The peak particle size and expanded uncertainties (95 % confidence interval) for two new particle calibration standards are measured as 101.8 nm ± 1.1 nm and 60.39 nm ± 0.63 nm. The particle samples are polystyrene spheres suspended in filtered, deionized water at a mass fraction of about 0.5 %. The size distribution measurements of aerosolized particles are made using a differential mobility analyzer (DMA) system calibrated using SRM® 1963 (100.7 nm polystyrene spheres). An electrospray aerosol generator was used for generating the 60 nm aerosol to almost eliminate the generation of multiply charged dimers and trimers and to minimize the effect of non-volatile contaminants increasing the particle size. The testing for the homogeneity of the samples and for the presence of multimers using dynamic light scattering is described. The use of the transfer function integral in the calibration of the DMA is shown to reduce the uncertainty in the measurement of the peak particle size compared to the approach based on the peak in the concentration vs. voltage distribution. A modified aerosol/sheath inlet, recirculating sheath flow, a high ratio of sheath flow to the aerosol flow, and accurate pressure, temperature, and voltage measurements have increased the resolution and accuracy of the measurements. A significant consideration in the uncertainty analysis was the correlation between the slip correction of the calibration particle and the measured particle. Including the correlation reduced the expanded uncertainty from approximately 1.8 % of the particle size to about 1.0 %. The effect of non-volatile contaminants in the polystyrene suspensions on the peak particle size and the uncertainty in the size is determined. The full size distributions for both the 60 nm and 100 nm spheres are tabulated and selected mean sizes including the number mean diameter and the dynamic light scattering mean diameter are computed. The use of these particles for calibrating DMAs and for

  14. Mutation of the nm23-H1 gene has a non-dominant role in colorectal adenocarcinoma

    PubMed Central

    JIN, YUELING; DAI, ZHENSHENG

    2016-01-01

    Nm23-H1 is a metastasis suppressor gene, which is has a reduced expression in patients with digestive system cancer. However, the mechanistic basis for the genetic instability remains unknown. To study the expression of the nm23-H1 gene in patients with colorectal cancer, polymerase chain reaction-single strand conformation polymorphism was used to analyze any point mutation, and immunohistochemistry was used to detect the expression of nm23-H1. Results revealed that all 63 specimens of Chinese human colorectal cancer tissues exhibit no point mutation. Among those 63 specimens, 19 (30%) exhibited positive immunostaining for the nm23-H1 protein and 44 (70%) exhibited negative immunostaining. These observations suggested that the protein and gene expression levels of nm23-H1 are reduced in colorectal cancer compared with the adjacent normal tissues, and the point mutation in the nm23-H1 gene is not the dominant cause of metastatic colorectal cancer. PMID:27330777

  15. Photodissociation of the Propargyl (C3D3) Radicals at 248 nm and 193 nm

    SciTech Connect

    Neumark., D.M.; Crider, P.E.; Castiglioni, L.; Kautzman, K.K.

    2009-01-21

    The photodissociation of perdeuterated propargyl (D{sub 2}CCCD) and propynyl (D{sub 3}CCC) radicals was investigated using fast beam photofragment translational spectroscopy. Radicals were produced from their respective anions by photodetachment at 540 nm and 450 nm (below and above the electron affinity of propynyl). The radicals were then photodissociated by 248 nm or 193 nm light. The recoiling photofragments were detected in coincidence with a time- and position-sensitive detector. Three channels were observed: D{sub 2} loss, CD + C{sub 2}D{sub 2}, and CD{sub 3} + C{sub 2}. Obervation of the D loss channel was incompatible with this experiment and was not attempted. Our translational energy distributions for D{sub 2} loss peaked at nonzero translational energy, consistent with ground state dissociation over small (< 1 eV) exit barriers with respect to separated products. Translational energy distributions for the two heavy channels peaked near zero kinetic energy, indicating dissociation on the ground state in the absence of exit barriers.

  16. Evaluation of the Diode laser (810nm,980nm) on dentin tubule diameter following internal bleaching

    PubMed Central

    Kiomarsi, Nazanin; Salim, Soheil; Sarraf, Pegah; Javad-Kharazifard, Mohammad

    2016-01-01

    Background The aim of this study was to evaluate the effect of diode laser irradiation and bleaching materials on the dentinal tubule diameter after laser bleaching. Material and Methods The dentin discs of 40 extracted third molar were used in this experiment. Each disc surface was divided into two halves by grooving. Half of samples were laser bleached at different wavelengths with two different concentrations of hydrogen peroxide. Other half of each disc with no laser bleaching remained as a negative control. Dentin discs were assigned randomly into four groups (n=10) with following hydrogen peroxide and diode laser wavelength specifications; Group 1 (30% - 810 nm), group 2 (30% - 980 nm), group 3 (46% - 810 nm) and group 4 (46% - 980 nm). All specimens were sent for scanning electron microscopic (SEM) analysis in order to measure tubular diameter in laser treated and control halves. Data were analyzed by ANOVA and Tukey test (p<0.05). Results A significant reduction in dentin tubule diameter was observed in groups 1, 2 and 4. There was no significant difference between groups 1 and 2 and between groups 3 and 4 after bleaching. Conclusions The SEM results showed that diode laser was able to reduce dentin tubule diameter and its effect on dentin was dependent on chemical action of bleaching material. Key words:Laser, diode, dentin, tubule, diameter. PMID:27398172

  17. THE SPECTRUM OF THORIUM FROM 250 nm TO 5500 nm: RITZ WAVELENGTHS AND OPTIMIZED ENERGY LEVELS

    SciTech Connect

    Redman, Stephen L.; Nave, Gillian; Sansonetti, Craig J.

    2014-03-01

    We have made precise observations of a thorium-argon hollow cathode lamp emission spectrum in the region between 350 nm and 1175 nm using a high-resolution Fourier transform spectrometer. Our measurements are combined with results from seven previously published thorium line lists to re-optimize the energy levels of neutral, singly, and doubly ionized thorium (Th I, Th II, and Th III). Using the optimized level values, we calculate accurate Ritz wavelengths for 19, 874 thorium lines between 250 nm and 5500 nm (40, 000 cm{sup –1} to 1800 cm{sup –1}). We have also found 102 new thorium energy levels. A systematic analysis of previous measurements in light of our new results allows us to identify and propose corrections for systematic errors in Palmer and Engleman and typographical errors and incorrect classifications in Kerber et al. We also found a large scatter with respect to the thorium line list of Lovis and Pepe. We anticipate that our Ritz wavelengths will lead to improved measurement accuracy for current and future spectrographs that make use of thorium-argon or thorium-neon lamps as calibration standards.

  18. The Spectrum of Thorium from 250 nm to 5500 nm: Ritz Wavelengths and Optimized Energy Levels

    NASA Astrophysics Data System (ADS)

    Redman, Stephen L.; Nave, Gillian; Sansonetti, Craig J.

    2014-03-01

    We have made precise observations of a thorium-argon hollow cathode lamp emission spectrum in the region between 350 nm and 1175 nm using a high-resolution Fourier transform spectrometer. Our measurements are combined with results from seven previously published thorium line lists to re-optimize the energy levels of neutral, singly, and doubly ionized thorium (Th I, Th II, and Th III). Using the optimized level values, we calculate accurate Ritz wavelengths for 19, 874 thorium lines between 250 nm and 5500 nm (40, 000 cm-1 to 1800 cm-1). We have also found 102 new thorium energy levels. A systematic analysis of previous measurements in light of our new results allows us to identify and propose corrections for systematic errors in Palmer & Engleman and typographical errors and incorrect classifications in Kerber et al. We also found a large scatter with respect to the thorium line list of Lovis & Pepe. We anticipate that our Ritz wavelengths will lead to improved measurement accuracy for current and future spectrographs that make use of thorium-argon or thorium-neon lamps as calibration standards.

  19. Optical constants determination of neodymium and gadolinium in the 3-nm to 100-nm wavelength range

    NASA Astrophysics Data System (ADS)

    Kjornrattanawanich, B.; Windt, D. L.; Uspenskii, Y. A.; Seely, J. F.

    2006-08-01

    The optical constants (n, k) of the wavelength-dependent index of refraction N = n+ik = 1-δ+ik of Nd (Neodymium) and Gd (Gadolinium) are determined in the wavelength range of 3 nm to 100 nm by the transmittance method using synchrotron radiation. Nd and Gd films with thicknesses ranging from 5 nm to 180 nm were fabricated on Si photodiodes (which served as the coating substrates as well as the detectors) and capped with Si layers to protect these reactive rare earth elements from oxidation. The imaginary part (k) obtained directly from the transmittance measurement is used in the derivation of the real part (δ) of the complex index of refraction N through the Kramers- Kronig integral. The measured optical constants are used in the design of currently developed Nd- and Gd-based multilayers for solar imaging applications. Our results on Nd and Gd optical constants and the reflectance of some Nd- and Gd-based multilayers are presented.

  20. NXT:1980Di immersion scanner for 7nm and 5nm production nodes

    NASA Astrophysics Data System (ADS)

    de Graaf, Roelof; Weichselbaum, Stefan; Droste, Richard; McLaren, Matthew; Koek, Bert; de Boeij, Wim

    2016-03-01

    Immersion scanners remain the critical lithography workhorses in semiconductor device manufacturing. When progressing towards the 7nm device node for logic and D18 device node for DRAM production, pattern-placement and layer-to-layer overlay requirements keep progressively scaling down and consequently require system improvements in immersion scanners. The on-product-overlay requirements are approaching levels of only a few nanometers, imposing stringent requirements on the scanner tool design in terms of reproducibility, accuracy and stability. In this paper we report on the performance of the NXT:1980Di immersion scanner. The NXT:1980Di builds upon the NXT:1970Ci, that is widely used for 16nm, 14nm and 10nm high-volume manufacturing. We will discuss the NXT:1980Di system- and sub-system/module enhancements that drive the scanner overlay, focus and productivity performance. Overlay, imaging, focus, productivity and defectivity data will be presented for multiple tools. To further reduce the on-product overlay system performance, alignment sensor contrast improvements as well as active reticle temperature conditioning are implemented on the NXT:1980Di. Reticle temperature conditioning will reduce reticle heating overlay and the higher contrast alignment sensor will improve alignment robustness for processed alignment targets. Due to an increased usage of multiple patterning techniques, an increased number of immersion exposures is required. NXT:1980Di scanner design modifications raised productivity levels from 250wph to 275wph. This productivity enhancement provides lower cost of ownership (CoO) for customers using immersion technology.

  1. Characterization of LANDSAT Panels Using the NIST BRDF Scale from 1100 nm to 2500 nm

    NASA Technical Reports Server (NTRS)

    Markham, Brian; Tsai, Benjamin K.; Allen, David W.; Cooksey, Catherine; Yoon, Howard; Hanssen, Leonard; Zeng, Jinan; Fulton, Linda; Biggar, Stuart; Markham, Brian

    2010-01-01

    Many earth observing sensors depend on white diffuse reflectance standards to derive scales of radiance traceable to the St Despite the large number of Earth observing sensors that operate in the reflective solar region of the spectrum, there has been no direct method to provide NIST traceable BRDF measurements out to 2500 rim. Recent developments in detector technology have allowed the NIST reflectance measurement facility to expand the operating range to cover the 250 nm to 2500 nm range. The facility has been modified with and additional detector using a cooled extended range indium gallium arsenide (Extended InGaAs) detector. Measurements were made for two PTFE white diffuse reflectance standards over the 1100 nm to 2500 nm region at a 0' incident and 45' observation angle. These two panels will be used to support the OLI calibration activities. An independent means of verification was established using a NIST radiance transfer facility based on spectral irradiance, radiance standards and a diffuse reflectance plaque. An analysis on the results and associated uncertainties will be discussed.

  2. Maskless plasmonic lithography at 22 nm resolution.

    PubMed

    Pan, Liang; Park, Yongshik; Xiong, Yi; Ulin-Avila, Erick; Wang, Yuan; Zeng, Li; Xiong, Shaomin; Rho, Junsuk; Sun, Cheng; Bogy, David B; Zhang, Xiang

    2011-01-01

    Optical imaging and photolithography promise broad applications in nano-electronics, metrologies, and single-molecule biology. Light diffraction however sets a fundamental limit on optical resolution, and it poses a critical challenge to the down-scaling of nano-scale manufacturing. Surface plasmons have been used to circumvent the diffraction limit as they have shorter wavelengths. However, this approach has a trade-off between resolution and energy efficiency that arises from the substantial momentum mismatch. Here we report a novel multi-stage scheme that is capable of efficiently compressing the optical energy at deep sub-wavelength scales through the progressive coupling of propagating surface plasmons (PSPs) and localized surface plasmons (LSPs). Combining this with airbearing surface technology, we demonstrate a plasmonic lithography with 22 nm half-pitch resolution at scanning speeds up to 10 m/s. This low-cost scheme has the potential of higher throughput than current photolithography, and it opens a new approach towards the next generation semiconductor manufacturing.

  3. Faster qualification of 193-nm resists for 100-nm development using photo cell monitoring

    NASA Astrophysics Data System (ADS)

    Jones, Chris M.; Kallingal, Chidam; Zawadzki, Mary T.; Jeewakhan, Nazneen N.; Kaviani, Nazila N.; Krishnan, Prakash; Klaum, Arthur D.; Van Ess, Joel

    2003-05-01

    The development of 100-nm design rule technologies is currently taking place in many R&D facilities across the world. For some critical alyers, the transition to 193-nm resist technology has been required to meet this leading edge design rule. As with previous technology node transitions, the materials and processes available are undergoing changes and improvements as vendors encounter and solve problems. The initial implementation of the 193-nm resits process did not meet the photolithography requirements of some IC manufacturers due to very high Post Exposure Bake temperature sensitivity and consequently high wafer to wafer CD variation. The photoresist vendors have been working to improve the performance of the 193-nm resists to meet their customer's requirements. Characterization of these new resists needs to be carried out prior to implementation in the R&D line. Initial results on the second-generation resists evaluated at Cypress Semicondcutor showed better CD control compared to the aelrier resist with comparable Depth of Focus (DOF), Exposure Latitute, Etch Resistance, etc. In addition to the standard lithography parameters, resist characterization needs to include defect density studies. It was found that the new resists process with the best CD control, resulted in the introduction of orders of magnitude higher yield limiting defects at Gate, Contact adn Local Interconnect. The defect data were shared with the resists vendor and within days of the discovery the resist vendor was able to pinpoint the source of the problem. The fix was confirmed and the new resists were successfully released to production. By including defect monitoring into the resist qualification process, Cypress Semiconductor was able to 1) drive correction actions earlier resulting in faster ramp and 2) eliminate potential yield loss. We will discuss in this paper how to apply the Micro Photo Cell Monitoring methodology for defect monitoring in the photolithogprhay module and the

  4. Absorption coefficients for water vapor at 193 nm from 300 to 1073 K

    NASA Technical Reports Server (NTRS)

    Kessler, W. J.; Carleton, K. L.; Marinelli, W. J.

    1993-01-01

    Measurements of the water absorption coefficient at 193 nm from 300 to 1073 K are reported. The measurements were made using broadband VUV radiation and a monochromator-based detection system. The water vapor was generated by a saturator and metered into a flowing, 99 cm absorption cell via a water vapor mass flow meter. The 193 nm absorption coefficient measurements are compared to room temperature and high temperature shock tube measurements with good agreement. The absorption can be parameterized by a nu3 vibrational mode reaction coordinate and the thermal population of the nu3 mode.

  5. Wettability control of a polymer surface through 126 nm vacuum ultraviolet light irradiation

    NASA Astrophysics Data System (ADS)

    Hozumi, Atsushi; Shirahata, Naoto; Nakanishi, Youichiro; Asakura, Shuuichi; Fuwa, Akio

    2004-07-01

    The control of the surface wettability of poly (methyl methacrylate) (PMMA) substrates has been successfully demonstrated using an Ar2* excimer lamp radiating 126 nm vacuum ultraviolet (VUV) light. Each of the samples was exposed to 126 nm VUV light in air over the pressure range of 2×10-4-105 Pa. Although at the process pressures of 10, 103, and 105 Pa, the PMMA surfaces became relatively hydrophilic, the degree of hydrophilicity depended markedly on the pressure. The minimum water contact angles of the samples treated at 10, 103, and 105 Pa were about 50°, 33°, and 64°, respectively. These values were larger than those of PMMA substrates hydrophilized through 172 nm VUV irradiation conducted under the same conditions. On the other hand, after 126 nm VUV irradiation conducted under the high vacuum condition of 2×10-4 Pa, the PMMA substrate surface became carbon-rich, probably due to preferential cross-linking reactions, as evidenced by x-ray photoelectron spectroscopy. This surface was hydrophobic, showing a water contact angle of about 101°. Although the 126 nm VUV-irradiated surfaces appeared relatively smooth when observed by atomic force microscope, very small particles with diameters of 30-60 nm, which probably originated from the readhesion of photodecomposed products, existed on all of the sample surfaces. .

  6. Distributed Humidity Sensing in PMMA Optical Fibers at 500 nm and 650 nm Wavelengths.

    PubMed

    Liehr, Sascha; Breithaupt, Mathias; Krebber, Katerina

    2017-03-31

    Distributed measurement of humidity is a sought-after capability for various fields of application, especially in the civil engineering and structural health monitoring sectors. This article presents a method for distributed humidity sensing along polymethyl methacrylate (PMMA) polymer optical fibers (POFs) by analyzing wavelength-dependent Rayleigh backscattering and attenuation characteristics at 500 nm and 650 nm wavelengths. Spatially resolved humidity sensing is obtained from backscatter traces of a dual-wavelength optical time domain reflectometer (OTDR). Backscatter dependence, attenuation dependence as well as the fiber length change are characterized as functions of relative humidity. Cross-sensitivity effects are discussed and quantified. The evaluation of the humidity-dependent backscatter effects at the two wavelength measurements allows for distributed and unambiguous measurement of relative humidity. The technique can be readily employed with low-cost standard polymer optical fibers and commercial OTDR devices.

  7. Polarization properties of lidar scattering from clouds at 347 nm and 694 nm.

    PubMed

    Pal, S R; Carswell, A I

    1978-08-01

    The polarization characteristics of lidar scattering from cumulus and low-lying shower clouds have been measured with a system operating at 694 nm (red) and 347 nm (blue). The backscatter profiles of the polarization components as well as of the total intensity of the return are presented and discussed for the two wavelengths. The linear depolarization ratio delta, which can be used as a measure of the unpolarized multiple scattering, has been obtained at both wavelengths. This quantity has a very low value at cloud base for both wavelengths and increases with pulse penetration. The blue registers generally higher values of a within the cloud. The measured total intensity backscatter functions for both wavelengths are presented and discussed in relation to theoretical calculations of cloud models.

  8. Novel 980-nm and 490-nm light sources using vertical cavity lasers with extended coupled cavities

    NASA Astrophysics Data System (ADS)

    McInerney, John G.; Mooradian, Aram; Lewis, Alan; Shchegrov, Andrei V.; Strzelecka, Eva M.; Lee, Dicky; Watson, Jason P.; Liebman, Michael K.; Carey, Glen P.; Umbrasas, Arvydas; Amsden, Charles A.; Cantos, Brad D.; Hitchens, William R.; Heald, David L.; Doan, Vincent V.; Cannon, J. L.

    2003-04-01

    We have developed novel electrically pumped, surface-emitting lasers emitting at 980 nm with an extended coupled cavity. The concept is scalable from monolithic low power devices all the way to high power extended cavity lasers. The latter have demonstrated 1W cw multi-mode and 0.5 W cw in a TEM00 mode and a single frequency, with 90% coupling efficiency into a single-mode fiber. By inserting a nonlinear optical medium in the external cavity, efficient and compact frequency doubling has been achieved with CW output powers 5-40 mW demonstrated at 490 nm. The latter devices are especially noteworthy due to their very low noise, sub 10 μrad beam pointing stability combined with small size, low power consumption and high efficiency.

  9. A 15 W 1152 nm Raman fiber laser with 6 nm spectral width for Ho3+-doped crystal's pumping source

    NASA Astrophysics Data System (ADS)

    Chen, Xiuyan; Jiang, Huawei

    2016-12-01

    A 11.5 W 1152 nm Raman fiber laser with 6 nm spectral width was demonstrated based on the resonator constructed with one fiber loop mirror and one fiber Bragg grating. By mans of experimental measurement and theoretical calculation, the reflectivity of the fiber loop mirror was confirmed as 0.93. The Yb3+-doped 1090 nm fiber length was about 5 m. When the maximum pumping power of 976 nm laser was 54.8 W, 32.2 W 1090 nm laser was obtained and the optical to optical conversion efficiency from 1090 nm to 1152 nm light was 48%. Finally, the 1152 nm Raman fiber laser was used for pumping Ho3+:LLF crystal, and the 1194 nm fluorescence emission peak was detected for the first time.

  10. Investigations of a dual seeded 1178nm Raman laser system

    NASA Astrophysics Data System (ADS)

    Block, Matthew; Henry, Leanne J.; Klopfer, Michael; Jain, Ravinder

    2016-03-01

    The leakage of 1121 nm power from a resonator cavity because of spectral broadening seriously degrades the performance of a Raman resonator by reducing the 1121 nm circulating power and the 1178 nm output power. Therefore, it is important to understand the conditions which minimize 1121 nm power leakage, maximize 1121 intracavity and 1178 nm output power while enabling a manageable Stimulated Brillouin Scattering gain for narrow linewidth systems. It was found that cavity lengths longer than approximately 40 m didn't result in significantly more 1121 nm linewidth broadening. Relative to the high reflectivity bandwidth of the fiber Bragg gratings, it was found that 4 nm FBGs seemed to optimize 1178 nm amplification while minimizing the amount of 1121 nm power leakage. A two stage high power 1178 nm Raman system was built and 20 W of 1178 nm output power was achieved with a polarization extinction ratio of 21 and nearly diffraction limited beam quality. Linewidth broadening was found to increase as the 1178 nm output increased and was approximately 8 GHz when the 1178 nm output power was 20 W. Because of the linewidth broadening, a co-pumped second Stokes Raman laser system is not useful for the sodium guidestar laser application which requires narrow linewidth.

  11. Multi-watt 589nm fiber laser source

    SciTech Connect

    DAWSON, J W; DROBSHOFF, A D; BEACH, R J; MESSERLY, M J; PAYNE, S A; BROWN, A; PENNINGTON, D M; BAMFORD, D J; SHARPE, S J; COOK, D J

    2006-01-19

    We have demonstrated 3.5W of 589nm light from a fiber laser using periodically poled stoichiometric Lithium Tantalate (PPSLT) as the frequency conversion crystal. The system employs 938nm and 1583nm fiber lasers, which were sum-frequency mixed in PPSLT to generate 589nm light. The 938nm fiber laser consists of a single frequency diode laser master oscillator (200mW), which was amplified in two stages to >15W using cladding pumped Nd{sup 3+} fiber amplifiers. The fiber amplifiers operate at 938nm and minimize amplified spontaneous emission at 1088nm by employing a specialty fiber design, which maximizes the core size relative to the cladding diameter. This design allows the 3-level laser system to operate at high inversion, thus making it competitive with the competing 1088nm 4-level laser transition. At 15W, the 938nm laser has an M{sup 2} of 1.1 and good polarization (correctable with a quarter and half wave plate to >15:1). The 1583nm fiber laser consists of a Koheras 1583nm fiber DFB laser that is pre-amplified to 100mW, phase modulated and then amplified to 14W in a commercial IPG fiber amplifier. As a part of our research efforts we are also investigating pulsed laser formats and power scaling of the 589nm system. We will discuss the fiber laser design and operation as well as our results in power scaling at 589nm.

  12. Multi-watt 589nm fiber laser source

    NASA Astrophysics Data System (ADS)

    Dawson, Jay W.; Drobshoff, Alex D.; Beach, Raymond J.; Messerly, Michael J.; Payne, Stephen A.; Brown, Aaron; Pennington, Deanna M.; Bamford, Douglas J.; Sharpe, Scott J.; Cook, David J.

    2006-02-01

    We have demonstrated 3.5W of 589nm light from a fiber laser using periodically poled stoichio-metric Lithium Tantalate (PPSLT) as the frequency conversion crystal. The system employs 938nm and 1583nm fiber lasers, which were sum-frequency mixed in PPSLT to generate 589nm light. The 938nm fiber laser consists of a single frequency diode laser master oscillator (200mW), which was amplified in two stages to >15W using cladding pumped Nd 3+ fiber amplifiers. The fiber amplifiers operate at 938nm and minimize amplified spontaneous emission at 1088nm by employing a specialty fiber design, which maximizes the core size relative to the cladding diameter. This design allows the 3-level laser system to operate at high inversion, thus making it competitive with the 1088nm 4-level laser transition. At 15W, the 938nm laser has an M2 of 1.1 and good polarization (correctable with a quarter and half wave plate to >15:1). The 1583nm fiber laser consists of a Koheras 1583nm fiber DFB laser that is pre-amplified to 100mW, phase modulated and then amplified to 14W in a commercial IPG fiber amplifier. As a part of our research efforts we are also investigating pulsed laser formats and power scaling of the 589nm system. We will discuss the fiber laser design and operation as well as our results in power scaling at 589nm.

  13. TUNABLE DIODE LASER MEASUREMENTS OF NO2 NEAR 670 NM AND 395 NM. (R823933)

    EPA Science Inventory

    Two single-mode diode lasers were used to record high-resolution absorption spectra of NO2 (dilute in Ar) near 670.2 and 394.5 nm over a range of temperatures (296 to 774 K) and total pressures (2.4 x 10(-2) to 1 atm). A commercial InGaAsP laser was tuned 1.3 cm(-1) at a repetiti...

  14. Electron-induced single event upsets in 28 nm and 45 nm bulk SRAMs

    DOE PAGES

    Trippe, J. M.; Reed, R. A.; Austin, R. A.; ...

    2015-12-01

    In this study, we present experimental evidence of single electron-induced upsets in commercial 28 nm and 45 nm CMOS SRAMs from a monoenergetic electron beam. Upsets were observed in both technology nodes when the SRAM was operated in a low power state. The experimental cross section depends strongly on both bias and technology node feature size, consistent with previous work in which SRAMs were irradiated with low energy muons and protons. Accompanying simulations demonstrate that δ-rays produced by the primary electrons are responsible for the observed upsets. Additional simulations predict the on-orbit event rates for various Earth and Jovian environmentsmore » for a set of sensitive volumes representative of current technology nodes. The electron contribution to the total upset rate for Earth environments is significant for critical charges as high as 0.2 fC. This value is comparable to that of sub-22 nm bulk SRAMs. Similarly, for the Jovian environment, the electron-induced upset rate is larger than the proton-induced upset rate for critical charges as high as 0.3 fC.« less

  15. A robust 45 nm gate-length CMOSFET for 90 nm Hi-speed technology

    NASA Astrophysics Data System (ADS)

    Lim, K. Y.; Chan, V.; Rengarajan, R.; Lee, H. K.; Rovedo, N.; Lim, E. H.; Yang, S.; Jamin, F.; Nguyen, P.; Lin, W.; Lai, C. W.; Teh, Y. W.; Lee, J.; Kim, L.; Luo, Z.; Ng, H.; Sudijono, J.; Wann, C.; Yang, I.

    2006-04-01

    We have developed a robust 45 nm gate-length CMOSFET for 90 nm node high performance application. Aggressive gate length and gate dielectric scaling along with optimized strain engineering enable high performance device similar to 65 nm node CMOSFET [Nakahara Y, et al. IEDM Tech Dig 2003;281] We have utilized oxy-nitride gate with post-nitridation anneal, high ramp rate spike anneal, low temperature spacer scheme and stress controlled SiN contact etch stop liner process in order to improve drive current as well as transistor short-channel roll-off. In particular, we will focus on the study of middle-of-line (MOL) process parameters, (i.e. MOL thermal expense and mechanical stress from contact etch stop liner) on transistor performance and reliability. Based on the study, we have obtained device exhibit drive-current of 900/485 μA/μm for NMOSFET and PMOSFET, respectively, at standard supply voltage of 1 V.

  16. Electron-induced single event upsets in 28 nm and 45 nm bulk SRAMs

    SciTech Connect

    Trippe, J. M.; Reed, R. A.; Austin, R. A.; Sierawski, B. D.; Weller, R. A.; Funkhouser, E. D.; King, M. P.; Narasimham, B.; Bartz, B.; Baumann, R.; Schrimpf, R. D.; Labello, R.; Nichols, J.; Weeden-Wright, S. L.

    2015-12-01

    In this study, we present experimental evidence of single electron-induced upsets in commercial 28 nm and 45 nm CMOS SRAMs from a monoenergetic electron beam. Upsets were observed in both technology nodes when the SRAM was operated in a low power state. The experimental cross section depends strongly on both bias and technology node feature size, consistent with previous work in which SRAMs were irradiated with low energy muons and protons. Accompanying simulations demonstrate that δ-rays produced by the primary electrons are responsible for the observed upsets. Additional simulations predict the on-orbit event rates for various Earth and Jovian environments for a set of sensitive volumes representative of current technology nodes. The electron contribution to the total upset rate for Earth environments is significant for critical charges as high as 0.2 fC. This value is comparable to that of sub-22 nm bulk SRAMs. Similarly, for the Jovian environment, the electron-induced upset rate is larger than the proton-induced upset rate for critical charges as high as 0.3 fC.

  17. FY09 assessment of mercury reduction at SNL/NM.

    SciTech Connect

    McCord, Samuel Adam

    2010-02-01

    This assessment takes the result of the FY08 performance target baseline of mercury at Sandia National Laboratories/New Mexico, and records the steps taken in FY09 to collect additional data, encourage the voluntary reduction of mercury, and measure success. Elemental (metallic) mercury and all of its compounds are toxic, and exposure to excessive levels can permanently damage or fatally injure the brain and kidneys. Elemental mercury can also be absorbed through the skin and cause allergic reactions. Ingestion of inorganic mercury compounds can cause severe renal and gastrointestinal damage. Organic compounds of mercury such as methyl mercury, created when elemental mercury enters the environment, are considered the most toxic forms of the element. Exposures to very small amounts of these compounds can result in devastating neurological damage and death.1 SNL/NM is required to report annually on the site wide inventory of mercury for the Environmental Protection Agency's (EPA) Toxics Release Inventory (TRI) Program, as the site's inventory is excess of the ten pound reportable threshold quantity. In the fiscal year 2008 (FY08) Pollution Prevention Program Plan, Section 5.3 Reduction of Environmental Releases, a performance target stated was to establish a baseline of mercury, its principle uses, and annual quantity or inventory. This was accomplished on July 29, 2008 by recording the current status of mercury in the Chemical Information System (CIS).

  18. Solution voltammetry of 4 nm magnetite iron oxide nanoparticles.

    PubMed

    Roberts, Joseph J P; Westgard, John A; Cooper, Laura M; Murray, Royce W

    2014-07-30

    The voltammetry of solution-dispersed magnetite iron oxide Fe3O4 nanoparticles is described. Their currents are controlled by nanoparticle transport rates, as shown with potential step chronoamperometry and rotated disk voltammetry. In pH 2 citrate buffer with added NaClO4 electrolyte, solution cyclic voltammetry of these nanoparticles (average diameter 4.4 ± 0.9 nm, each containing ca. 30 Fe sites) displays an electrochemically irreversible oxidation with E(PEAK) at ca. +0.52 V and an irreversible reduction with E(PEAK) at ca. +0.2 V vs Ag/AgCl reference electrode. These processes are presumed to correspond to the formal potentials for one-electron oxidation of Fe(II) and reduction of Fe(III) at their different sites in the magnetite nanoparticle structure. The heterogeneous electrode reaction rates of the nanoparticles are very slow, in the 10(-5) cm/s range. The nanoparticles are additionally characterized by a variety of tools, e.g., TEM, UV/vis, and XPS spectroscopies.

  19. Inflammatory Cytokine Expression and Sebum Production after Exposure of Cultured Human Sebocytes to Ultraviolet A Radiation and Light at Wavelengths of 650 nm and 830 nm

    PubMed Central

    Chae, Soo Yuhl; Ryu, Hyo Sub; Jang, Yong Hyun; Lee, Seok-Jong; Kim, Do Won

    2015-01-01

    Background The effectiveness of ultraviolet (UV) radiation, visible light, or infrared light therapy for the treatment of acne is the subject of ongoing scientific debate. Objective This study was conducted to investigate changes in sebum production and the expression of inflammatory cytokines, matrix metalloproteinases (MMPs), and antimicrobial peptides (AMPs), following exposure of cultured human sebocytes to UVA radiation and light at wavelengths of 650 nm and 830 nm. Methods Reverse transcription polymerase chain reaction assays were performed to measure the gene expression levels of inflammatory cytokines (interleukin [IL]-1β, IL-6, IL-8, and tumor necrosis factor-α), MMPs (MMP-1, MMP-3, and MMP-9), and AMPs (psoriasin, hBD-2, hBD-3, and LL-37) in cultured sebocytes after exposure to UVA radiation (2 J/cm2, 3 J/cm2, and 5 J/cm2) and light at wavelengths of 650 nm (14 J/cm2, 29 J/cm2, and 87 J/cm2) and 830 nm (5 J/cm2, 10 J/cm2, and 30 J/cm2). Expression of inflammatory cytokine proteins and sebum production were measured using enzyme-linked immunoassays and a lipid analysis kit, respectively. Results Exposure of cultured sebocytes to UVA radiation and light at wavelengths of 650 nm and 830 nm did not show a significant increase in the expression of inflammatory cytokines, MMPs, or AMPs. Sebum production was not significantly decreased after exposure to UVA radiation and light at both wavelengths. Conclusion We propose that UVA radiation, visible light, and infrared light can be used to target Propionibacterium acnes for the treatment of acne, without an increase in the expression of inflammatory biomarkers and sebum production. PMID:25834355

  20. Quantum yield for carbon monoxide production in the 248 nm photodissociation of carbonyl sulfide (OCS)

    NASA Technical Reports Server (NTRS)

    Zhao, Z.; Stickel, R. E.; Wine, P. H.

    1995-01-01

    Tunable diode laser absorption spectroscopy has been coupled with excimer laser flash photolysis to measure the quantum yield for CO production from 248 nm photodissociation of carbonyl sulfide (OCS) relative to the well-known quantum yield for CO production from 248 nm photolysis of phosgene (Cl2CO2). The temporal resolution of the experiments was sufficient to distinguish CO formed directly by photodissociation from that formed by subsequent S((sup 3)P(sub J)) reaction with OCS. Under the experimental conditions employed, CO formation via the fast S((sup 1)D(sub 2)) + OCS reaction was minimal. Measurements at 297K and total pressures from 4 to 100 Torr N2 + N2O show the CO yield to be greater than 0.95 and most likely unity. This result suggests that the contribution of OCS as a precursor to the lower stratospheric sulfate aerosol layer is somewhat larger than previously thought.

  1. Studies on a cross-linking type positive 193nm photoresist material

    NASA Astrophysics Data System (ADS)

    Wang, Liyuan; Guo, Xin; Chu, Zhanxing; Wang, Wenjun

    2006-03-01

    A kind of diacid, acrylpimaric acid, with condensed alicyclic structure and good film-forming property, was prepared by the Diels-Alder reaction of abietic acid and acrylic acid. In their solid film, the diacid can react with divinyl ether, such as 1,3-divinyloxyethoxybenzene when baked above 80 °C and become insoluble in dilute aqueous base. Thus formed compound can be quickly decomposed at the presence of strong acid generated by PAG above 100 °C and become easily soluble in dilute aqueous base. A positive photoresist can be formed by the diacid, divinyl ether and PAG. The measured photosensitivity is less than 50 mj/cm2 when exposed to low pressure Hg lamp (254nm). The diacid mixture displayed lower transparency than estimated at 193 nm and should be further purified to be used in 193 nm photoresist.

  2. Cell projection use in maskless lithography for 45nm and 32nm logic nodes

    NASA Astrophysics Data System (ADS)

    Manakli, S.; Komami, H.; Takizawa, M.; Mitsuhashi, T.; Pain, L.

    2009-03-01

    Due to the ever-increasing cost of equipment and mask complexity, the use of optical lithography for integrated circuit manufacturing is increasingly more complex and expensive. Recent workshops and conferences in semiconductor lithography underlined that one alternative to support sub-32nm technologies is mask-less lithography option using electron beam technology. However, this direct write approach based on variable shaped beam principle (VSB) is not sufficient in terms of throughput, i.e. of productivity. New direct write techniques like multibeam systems are under development, but these solutions will not be mature before 2012. The use of character/cell projection (CP) on industrial VSB tools is the first step to deal with the throughput concerns. This paper presents the status of the CP technology and evaluates its possible use for the 45nm and 32nm logic nodes. It will present standard cell and SRAM structures that are printed as single characters using the CP technique. All experiments are done using the Advantest tool (F3000) which can project up to 100 different cells per layer. Cell extractions and design have been performed with the design and software solution developed by D2S. In this paper, we first evaluate the performance gain that can be obtained with the CP approach compared to the standard VSB approach. This paper also details the patterning capability obtained by using the CP concept. An evaluation of the CD uniformity and process stability is also presented. Finally this paper discusses about the improvements of this technique to address high resolution and to improve the throughput concerns.

  3. Manufacturability of 2x-nm devices with EUV tool

    NASA Astrophysics Data System (ADS)

    Tawarayama, Kazuo; Nakajima, Yumi; Kyoh, Suigen; Aoyama, Hajime; Matsunaga, Kentaro; Magoshi, Shunko; Tanaka, Satoshi; Hayashi, Yumi; Mori, Ichiro

    2011-04-01

    Due to the promising development status of EUVL as a practical lithography technology for the 2x-nm node, we are continuing to evaluate its process liability using the EUV1 at Selete, which has an Off-Axis illumination capability. The resolution limit of the EUV1 for L&S patterns is currently 18 nm for dipole illumination, and 16 nm for aggressive dipole illumination. This study examined the critical points of EUVL for device manufacturing through wafer processes. The yield obtained from electrical measurements indicates the maturity of the technology, including the resist process, the tool, and the mask. Optimization of the resist and RIE processes significantly improved the yield. The final yields obtained from electrical measurements were 100% for hp 30 nm, 70% for hp 28 nm, and 40% for hp 26 nm. These results demonstrate EUV lithography to be a practical technology that is now suitable for 2x nm semiconductor manufacture.

  4. The electrochemisty of surface modified <10 nm metal oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Roberts, Joseph J. P.

    and ZrO2 nanoparticles was also explored, but resulted in very low surface coverages. ZrO2 nanoparticles were also ferrocene tagged using previously discussed siloxane chemistry as well as a new route using click chemistry with an azo-phosphate ligand. A similar approach was taken with hydrolytically synthesized IrO 2 and is included for comparison. Chapter Five studies the multivalent electrochemistry of 4 nm magnetite nanoparticles. These nanoparticles are synthesized via thermal degradation and capped with citric acid to make them water soluble. pH dependent electrochemistry was discovered and characterized using cyclic voltammetry, chronoamperometry, and rotating disk electrode experiments. Two separate electrochemical species are present and undergo two irreversible, but separate electrochemical reactions; Fe(II) → Fe (III) and Fe(III) → Fe(II).

  5. Ultraviolet 320 nm laser excitation for flow cytometry.

    PubMed

    Telford, William; Stickland, Lynn; Koschorreck, Marco

    2017-02-27

    Although multiple lasers and high-dimensional analysis capability are now standard on advanced flow cytometers, ultraviolet (UV) lasers (usually 325-365 nm) remain an uncommon excitation source for cytometry. This is primarily due to their cost, and the small number of applications that require this wavelength. The development of the Brilliant Ultraviolet (BUV fluorochromes, however, has increased the importance of this formerly niche excitation wavelength. Historically, UV excitation was usually provided by water-cooled argon- and krypton-ion lasers. Modern flow cytometers primary rely on diode pumped solid state lasers emitting at 355 nm. While useful for all UV-excited applications, DPSS UV lasers are still large by modern solid state laser standards, and remain very expensive. Smaller and cheaper near UV laser diodes (NUVLDs) emitting at 375 nm make adequate substitutes for 355 nm sources in many situations, but do not work as well with very short wavelength probes like the fluorescent calcium chelator indo-1. In this study, we evaluate a newly available UV 320 nm laser for flow cytometry. While shorter in wavelength that conventional UV lasers, 320 is close to the 325 nm helium-cadmium wavelength used in the past on early benchtop cytometers. A UV 320 nm laser was found to excite almost all Brilliant Ultraviolet dyes to nearly the same level as 355 nm sources. Both 320 nm and 355 nm sources worked equally well for Hoechst and DyeCycle Violet side population analysis of stem cells in mouse hematopoetic tissue. The shorter wavelength UV source also showed excellent excitation of indo-1, a probe that is not compatible with NUVLD 375 nm sources. In summary, a 320 nm laser module made a suitable substitute for conventional 355 nm sources. This laser technology is available in a smaller form factor than current 355 nm units, making it useful for small cytometers with space constraints. © 2017 International Society for Advancement of Cytometry.

  6. Sidewall spacer quadruple patterning for 15nm half-pitch

    NASA Astrophysics Data System (ADS)

    Xu, Ping; Chen, Yongmei; Chen, Yijian; Miao, Liyan; Sun, Shiyu; Kim, Sung-Woo; Berger, Ami; Mao, Daxin; Bencher, Christ; Hung, Raymond; Ngai, Chris

    2011-04-01

    193nm immersion lithography, with the single-exposure resolution limitation of half-pitch 38nm, has extended its patterning capability to about 20nm using the double-patterning technique[1]. Despite the non-trivial sub-20nm patterning challenges, several NAND Flash manufacturers are already pursuing for sub-16nm patterning technology. 25nm NAND flash memory has already begun production in 2010, and given the typical 2-year scaling cycle, sub-16nm NAND devices should see pilot or mass production as early as 2014. Using novel patterning techniques such as sidewall spacer quadruple patterning (upon 120nm to 128nm pitch using dry ArF lithography) or triple patterning (upon 90nm pitch using immersion ArF lithography), we are able to extend optical lithography to sub-16nm half-pitch and demonstrate the lithographic performance that can nearly meet the ITRS roadmap requirements. In this paper, we conduct an in-depth review and demonstration of sidewall spacer quadruple patterning; including 300mm wafer level data of the mean values and CDU along with a mathematical assessment of the various data pools for sub-16nm lines and spaces. By understanding which processes (lithography, deposition, and etch) define the critical dimension of each data pool, we can make predictions of CDU capability for the sidewall spacer quad patterning. Our VeritySEM4i CD SEM tool demonstrated high measurement yield during fully automated measurements, which enables accurate lines, spaces and CDU measurements of the sub-16nm. The patterns generated from the sidewall spacer quadruple patterning techniques are used as a hardmask to transfer sub-16nm lines and spaces patterns to underneath amorphous silicon and silicon oxide layers, or poly silicon layer for 1X STI or poly gate applications.

  7. Measurements of Stokes parameters of materials at 1064-nm and 532-nm wavelengths

    NASA Astrophysics Data System (ADS)

    Tan, Songxin; Narayanan, Ram M.; Kalshoven, James E., Jr.

    2001-09-01

    Laser radar systems have found wide applications in the field of remote sensing. Reflectance as well as polarization features are used together for applications ranging from environmental monitoring to target classification. The Stokes parameters are ideal quantities for characterizing the above features because they provide useful information on both light intensity and polarization state. The University of Nebraska is currently refurbishing an airborne multi-wavelength laser radar system based on the NASA Goddard Space Flight Center (GSFC) developed Airborne Laser Polarimetric Sensor (ALPS). The system uses a Nd:YAG laser operating at wavelengths of 1064 nm and 532 nm, and contains four channels at each wavelength to measure the polarization states. This system was used to measure the Stokes parameters of backscattered laser light from different materials. These included canvas tarp, white paper, plywood, concrete, aluminum plate and anodized aluminum plate. The data provide an understanding of the polarized scattering properties of various materials, and are expected to be useful in developing target discrimination algorithms.

  8. Ultralow-Power Electronic Trapping of Nanoparticles with Sub-10 nm Gold Nanogap Electrodes.

    PubMed

    Barik, Avijit; Chen, Xiaoshu; Oh, Sang-Hyun

    2016-10-12

    We demonstrate nanogap electrodes for rapid, parallel, and ultralow-power trapping of nanoparticles. Our device pushes the limit of dielectrophoresis by shrinking the separation between gold electrodes to sub-10 nm, thereby creating strong trapping forces at biases as low as the 100 mV ranges. Using high-throughput atomic layer lithography, we manufacture sub-10 nm gaps between 0.8 mm long gold electrodes and pattern them into individually addressable parallel electronic traps. Unlike pointlike junctions made by electron-beam lithography or larger micron-gap electrodes that are used for conventional dielectrophoresis, our sub-10 nm gold nanogap electrodes provide strong trapping forces over a mm-scale trapping zone. Importantly, our technology solves the key challenges associated with traditional dielectrophoresis experiments, such as high voltages that cause heat generation, bubble formation, and unwanted electrochemical reactions. The strongly enhanced fields around the nanogap induce particle-transport speed exceeding 10 μm/s and enable the trapping of 30 nm polystyrene nanoparticles using an ultralow bias of 200 mV. We also demonstrate rapid electronic trapping of quantum dots and nanodiamond particles on arrays of parallel traps. Our sub-10 nm gold nanogap electrodes can be combined with plasmonic sensors or nanophotonic circuitry, and their low-power electronic operation can potentially enable high-density integration on a chip as well as portable biosensing.

  9. Challenges in the Plasma Etch Process Development in the sub-20nm Technology Nodes

    NASA Astrophysics Data System (ADS)

    Kumar, Kaushik

    2013-09-01

    For multiple generations of semiconductor technologies, RF plasmas have provided a reliable platform for critical and non-critical patterning applications. The electron temperature of processes in a RF plasma is typically several electron volts. A substantial portion of the electron population is within the energy range accessible for different types of electron collision processes, such as electron collision dissociation and dissociative electron attachment. When these electron processes occur within a small distance above the wafer, the neutral species, radicals and excited molecules, generated from these processes take part in etching reactions impacting selectivity, ARDE and micro-loading. The introduction of finFET devices at 22 nm technology node at Intel marks the transition of planar devices to 3-dimensional devices, which add to the challenges to etch process in fabricating such devices. In the sub-32 nm technology node, Back-end-of-the-line made a change with the implementation of Trench First Metal Hard Mask (TFMHM) integration scheme, which has hence gained traction and become the preferred integration of low-k materials for BEOL. This integration scheme also enables Self-Aligned Via (SAV) patterning which prevents via CD growth and confines via by line trenches to better control via to line spacing. In addition to this, lack of scaling of 193 nm Lithography and non-availability of EUV based lithography beyond concept, has placed focus on novel multiple patterning schemes. This added complexity has resulted in multiple etch schemes to enable technology scaling below 80 nm Pitches, as shown by the memory manufacturers. Double-Patterning and Quad-Patterning have become increasingly used techniques to achieve 64 nm, 56 nm and 45 nm Pitch technologies in Back-end-of-the-line. Challenges associated in the plasma etching of these multiple integration schemes will be discussed in the presentation. In collaboration with A. Ranjan, TEL Technology Center, America

  10. Expression of NM23 in human melanoma progression and metastasis.

    PubMed Central

    Easty, D. J.; Maung, K.; Lascu, I.; Véron, M.; Fallowfield, M. E.; Hart, I. R.; Bennett, D. C.

    1996-01-01

    NM23 is a putative metastasis-suppressor gene for some human cancers. Here we have studied NM23 expression during melanoma progression using Northern blotting and immunocytochemistry. There was no significant difference in the average amounts of NM23 mRNA between cell lines derived from metastatic and primary melanomas. The level of NM23 mRNA was also determined for three pairs of poorly metastatic parental (P) and their highly metastatic variant (M) cell lines; the ratios for M/P were 1.2, 0.98 and 0.80. Next we used immunocytochemistry to study NM23 protein in normal skin, benign naevi and primary and metastatic melanomas. Melanocytes in all normal skin and benign samples were positive for NM23; however most primary melanomas (7/11) were not stained by the antibody. All metastatic melanoma samples (5/5) were positively stained. Findings were similar with an antiserum reactive with both forms of NM23 (H1 and H2), and with an antibody specific for NM23-H1. No relationship was apparent between NM23 immunoreactivity in primary tumours and their aggressiveness or prognosis. Hence, in contrast to the situation described for murine melanoma, the amount of NM23 mRNA or protein in human melanoma did not correlate inversely with metastasis. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:8679442

  11. Segmentation of the macular choroid in OCT images acquired at 830nm and 1060nm

    NASA Astrophysics Data System (ADS)

    Lee, Sieun; Beg, Mirza F.; Sarunic, Marinko V.

    2013-06-01

    Retinal imaging with optical coherence tomography (OCT) has rapidly advanced in ophthalmic applications with the broad availability of Fourier domain (FD) technology in commercial systems. The high sensitivity afforded by FD-OCT has enabled imaging of the choroid, a layer of blood vessels serving the outer retina. Improved visualization of the choroid and the choroid-sclera boundary has been investigated using techniques such as enhanced depth imaging (EDI), and also with OCT systems operating in the 1060-nm wavelength range. We report on a comparison of imaging the macular choroid with commercial and prototype OCT systems, and present automated 3D segmentation of the choroid-scleral layer using a graph cut algorithm. The thickness of the choroid is an important measurement to investigate for possible correlation with severity, or possibly early diagnosis, of diseases such as age-related macular degeneration.

  12. A precise measurement of lunar spectral irradiance from 450 nm to 1000 nm

    NASA Astrophysics Data System (ADS)

    Cramer, C. E.; Lykke, K.; Woodward, J. T.; Smith, A. W.

    2013-12-01

    Although the Moon is our nearest celestial neighbor, our knowledge of its absolute spectral irradiance is an order of magnitude less precise than our knowledge of the best-calibrated stars, including the Sun. A precise determination of the Moon's absolute spectral irradiance has the potential to improve on-orbit calibrations of Earth-observing instruments and extend atmospheric monitoring techniques based on Sun photometry to nighttime measurements based on lunar spectrophotometry. Observations of the Moon have already been used to track changes in satellite sensor response at the sub-percent level, relying on a model of lunar irradiance developed by the United States Geological Survey to predict time-dependent changes in lunar irradiance. The absolute scale of this model, however, is not known accurately enough to allow the Moon to specify an absolute scale for instrument response on orbit or to bridge gaps in various climate data records. We report initial measurements of lunar spectral irradiance with an uncertainty below 1 % from 420 nm to 1000 nm and compare them with the USGS model. Our measurement uncertainty meets the radiometric calibration requirement for many climate data records derived from satellite images, including those for vegetation, aerosols, and snow and ice albedo. It therefore opens the possibility of using the Moon as a calibration standard to bridge gaps in satellite coverage and validate atmospheric retrieval algorithms. Our measurement technique also yields detailed information about the atmosphere at the measurement site, suggesting that lunar observations are a possible solution for aerosol monitoring during the polar winter and can provide nighttime measurements to complement aerosol data collected with Sun photometers. Our measurement, made with a novel apparatus, is an order of magnitude more accurate than the previous state-of-the-art and has continuous spectral coverage, removing the need to interpolate between filter passbands.

  13. Sub-10 nm patterning using EUV interference lithography.

    PubMed

    Päivänranta, Birgit; Langner, Andreas; Kirk, Eugenie; David, Christian; Ekinci, Yasin

    2011-09-16

    Extreme ultraviolet (EUV) lithography is currently considered as the leading technology for high-volume manufacturing below sub-20 nm feature sizes. In parallel, EUV interference lithography based on interference transmission gratings has emerged as a powerful tool for industrial and academic research. In this paper, we demonstrate nanopatterning with sub-10 nm resolution using this technique. Highly efficient and optimized molybdenum gratings result in resolved line/space patterns down to 8 nm half-pitch and show modulation down to 6 nm half-pitch. These results show the performance of optical nanopatterning in the sub-10 nm range and currently mark the record for photon-based lithography. Moreover, an efficient phase mask completely suppressing the zeroth-order diffraction and providing 50 nm line/space patterns over large areas is evaluated. Such efficient phase masks pave the way towards table-top EUV interference lithography systems.

  14. 32nm node technology development using interference immersion lithography

    NASA Astrophysics Data System (ADS)

    Sewell, Harry; McCafferty, Diane; Markoya, Louis; Hendrickx, Eric; Hermans, Jan; Ronse, Kurt

    2005-05-01

    The 38nm and 32nm lithography nodes are the next major targets for optical lithography on the Semiconductor Industry Roadmap. The recently developed water-based immersion lithography using ArF illumination will be able to provide an optical solution for lithography at the 45nm node, but it will not be able to achieve the 38nm or the 32nm nodes as currently defined. To achieve these next lithographic nodes will require new, very high refractive index fluids to replace the water used in current immersion systems. This paper describes tests and experiments using an interference immersion lithography test jig to develop key technology for the 32nm node. Interference imaging printers have been available for years, and with the advent of Immersion Lithography, they have a new use. Interference immersion image printing offers users a rapid, cost-effective way to develop immersion lithography, particularly at extremely high resolutions. Although it can never replace classical lens-based lithography systems for semiconductor device production, it does offer a way to develop resist and fluid technology at a relatively low cost. Its simple image-forming format offers easy access to the basic physics of advanced imaging. Issues such as: Polarization of the image forming light rays; Fluid/resist interaction during exposure; Topcoat film performance; and the Line Edge Roughness (LER) of resists at extremely high resolutions can all be readily studied. Experiments are described and results are provided for work on: 32nm imaging tests; high refractive index fluid testing using 193nm wavelength at resolutions well beyond current lens-based system capabilities; and polarization configuration testing on 45nm, 38nm, and 32nm L/S features. Results on the performance of resists and topcoats are reported for 32nm L/S features.

  15. Detection limits of 405 nm and 633 nm excited PpIX fluorescence for brain tumor detection during stereotactic biopsy

    NASA Astrophysics Data System (ADS)

    Markwardt, Niklas; Götz, Marcus; Haj-Hosseini, Neda; Hollnburger, Bastian; Sroka, Ronald; Stepp, Herbert; Zelenkov, Petr; Rühm, Adrian

    2016-04-01

    5-aminolevulinic-acid-(5-ALA)-induced protoporphyrin IX (PpIX) fluorescence may be used to improve stereotactic brain tumor biopsies. In this study, the sensitivity of PpIX-based tumor detection has been investigated for two potential excitation wavelengths (405 nm, 633 nm). Using a 200 μm fiber in contact with semi-infinite optical phantoms containing ink and Lipovenös, PpIX detection limits of 4.0 nM and 200 nM (relating to 1 mW excitation power) were determined for 405 nm and 633 nm excitation, respectively. Hence, typical PpIX concentrations in glioblastomas of a few μM should be well detectable with both wavelengths. Additionally, blood layers of selected thicknesses were placed between fiber and phantom. Red excitation was shown to be considerably less affected by blood interference: A 50 μm blood layer, for instance, blocked the 405- nm-excited fluorescence completely, but reduced the 633-nm-excited signal by less than 50%. Ray tracing simulations demonstrated that - without blood layer - the sensitivity advantage of 405 nm rises for decreasing fluorescent volume from 50-fold to a maximum of 100-fold. However, at a tumor volume of 1 mm3, which is a typical biopsy sample size, the 633-nm-excited fluorescence signal is only reduced by about 10%. Further simulations revealed that with increasing fiber-tumor distance, the signal drops faster for 405 nm. This reduces the risk of detecting tumor tissue outside the needle's coverage, but diminishes the overlap between optically and mechanically sampled volumes. While 405 nm generally offers a higher sensitivity, 633 nm is more sensitive to distant tumors and considerably superior in case of blood-covered tumor tissue.

  16. Generation and use of high power 213 nm and 266 nm laser radiation and tunable 210-400 nm laser radiation with BBO crystal matrix array

    DOEpatents

    Gruen, Dieter M.

    2000-01-01

    A 213 nm laser beam is capable of single photon ablative photodecomposition for the removal of a polymer or biological material substrate. Breaking the molecular bonds and displacing the molecules away from the substrate in a very short time period results in most of the laser photon energy being carried away by the displaced molecules, thus minimizing thermal damage to the substrate. The incident laser beam may be unfocussed and is preferably produced by quintupling the 1064 nm radiation from a Nd:YAG solid state laser, i.e., at 213 nm. In one application, the 213 nm laser beam is expanded in cross section and directed through a plurality of small beta barium borate (BBO) crystals for increasing the energy per photon of the laser radiation directed onto the substrate. The BBO crystals are arranged in a crystal matrix array to provide a large laser beam transmission area capable of accommodating high energy laser radiation without damaging the BBO crystals. The BBO crystal matrix array may also be used with 266 nm laser radiation for carrying out single or multi photon ablative photodecomposition. The BBO crystal matrix array may also be used in an optical parametric oscillator mode to generate high power tunable laser radiation in the range of 210-400 nm.

  17. The OH + HBr reaction revisited

    NASA Technical Reports Server (NTRS)

    Ravishankara, A. R.; Wine, P. H.; Wells, J. R.

    1985-01-01

    Variable-temperature measurements of the rate coefficient /k(1)/ for the reaction OH + HBr yield Br + H2O are presented. The measurements are verified by two techniques: one involved a 266-nm pulsed-laser photolysis of O3/H2O/HBr/He mixtures in conjunction with time-resolved resonance fluorescence detection of OH, the second comprised pulsed laser-induced fluorescence detection of OH following 248-nm pulsed-laser photolysis of H2O2/HBr/Ar mixtures. It is reported that k(1) = (11.9 + or -1.4 x 10 to the -12th (cu cm)/(molecule)(s) independent of temperature. The measurements are compared with other available results.

  18. Evaluation of dental pulp repair using low level laser therapy (688 nm and 785 nm) morphologic study in capuchin monkeys

    NASA Astrophysics Data System (ADS)

    Pretel, H.; Oliveira, J. A.; Lizarelli, R. F. Z.; Ramalho, L. T. O.

    2009-02-01

    The aim of this study was to evaluate the hypothesis that low-level laser therapy (LLLT) 688 nm and 785 nm accelerate dentin barrier formation and repair process after traumatic pulp exposure. The sample consisted of 45 premolars of capuchin monkeys (Cebus apella) with pulp exposure Class V cavities. All premolars were treated with calcium hydroxide (Ca(OH)2), divided in groups of 15 teeth each, and analyzed on 7th, 25th, and 60th day. Group GI - only Ca(OH)2, GII - laser 688 nm, and GIII - laser 785 nm. Laser beam was used in single and punctual dose with the parameters: continuous, 688 nm and 785 nm wavelength, tip's area of 0.00785 cm2, power 50 mW, application time 20 s, dose 255 J/cm2, energy 2 J. Teeth were capped with Ca(OH)2, Ca(OH)2 cement and restored with amalgam. All groups presented pulp repair. On 25th day the thickness of the formed dentin barrier was different between the groups GI and GII (p < 0.05) and between groups GI and GIII (p < 0.01). On 60th day there was difference between GI and GIII (p < 0.01). It may be concluded that, LLLT 688 nm and 785 nm accelerated dentin barrier formation and consequently pulp repair process, with best results using infrared laser 785 nm.

  19. Scattering matrices of martian dust analogs at 488 nm and 647 nm

    NASA Astrophysics Data System (ADS)

    Dabrowska, Dominika D.; Muñoz, Olga; Moreno, Fernando; Ramos, José L.; Martínez-Frías, Jesús; Wurm, Gerhard

    2015-04-01

    We present measurements of the complete scattering matrix as a function of the scattering angle of five martian dust analogs, namely montmorillonite, two palagonite (JSC-1) samples, basalt, and calcite. The measurements are performed at 488 and 647 nm, covering the scattering angle range from 3° to 177°. The experimental scattering matrices are compared with results of Lorenz-Mie calculations performed for the same size distributions and refractive indices as our analog samples. As expected, we find that scattering matrices of realistic polydispersions of dust particles cannot be replaced by such calculated matrices. In contrast, the measured phase functions for our martian dust analogs may be considered a good approximation for martian dust at the studied wavelengths. Further, because of the sensitivity of polarimetry to particle microphysics, spectro-polarimetric observations from the martian surface appear to be a powerful diagnostic tool to infer the composition of the dust in the martian atmosphere. To facilitate the use of the experimental matrices for multiple-scattering calculations with polarization included, we compute the corresponding synthetic scattering matrices based on the measurements and defined in the full angle range from 0° to 180°.

  20. On high speed transmission with the 850nm VCSELs

    NASA Astrophysics Data System (ADS)

    Turkiewicz, Jarosław P.; Chorchos, Łukasz; Puerta Ramirez, Rafael; Vegas Olmos, Juan Jose; Ledentsov, Nikolay

    2016-09-01

    One of the key research challenges is development of energy efficient high bit rate data interconnects. The most promising solutions are based on 850 nm vertical cavity surface emitting lasers (VCSEL) and multi mode fibre (MMF). In this paper options to realize energy efficient 850 nm data interconnects are discussed and evaluated.

  1. Competition between photochemistry and energy transfer in ultraviolet-excited diazabenzenes. I. Photofragmentation studies of pyrazine at 248 nm and 266 nm

    SciTech Connect

    Sevy, Eric T.; Muyskens, Mark A.; Rubin, Seth M.; Flynn, George W.; Muckerman, James T.

    2000-04-01

    The quantum yield for the formation of HCN from the photodissociation of pyrazine excited at 248 nm and 266 nm is determined by IR diode probing of the HCN photoproduct. HCN photoproducts from excited pyrazine are produced via three different dissociation channels, one that is extremely ''prompt'' and two others that are ''late.'' The total quantum yield from all reaction channels obtained at low quencher gas pressures, {phi}=1.3{+-}0.2 for 248 nm and 0.5{+-}0.3 for 266 nm, is in agreement with preliminary studies of this process as well as recent molecular beam studies. To investigate if HCN production is the result of pyrazine multiphoton absorption, this photodissociation process has been further studied by observing the HCN quantum yield as a function of total quencher gas pressure (10 mTorr pyrazine, balance SF{sub 6}) and as a function of 248 nm laser fluence from 2.8 to 82 mJ/cm2. At the highest SF{sub 6} pressures, the HCN quantum yield shows strong positive correlation with laser fluence, indicating that the ''prompt'' channel is the result of multiphoton absorption; however, at low pressure, the HCN quantum yield is affected little by changing laser fluence, indicating that the majority of the HCN photoproducts at low pressure are produced from pyrazine which has absorbed only one UV photon. At the lowest pressures sampled, HCN produced from the one-photon ''late'' process accounts for more than 95% of all HCN formed (at low laser fluence). At high pressures the single photon ''late'' pyrazine dissociation is quenched, and HCN produced at high quencher gas pressures comes only from the multiphoton absorption channel, which can be clearly observed to depend on laser fluence. The HCN quantum yield as a function of laser intensity at high pressure has been fit to a quadratic function that can be used to determine the amount of ''prompt'' ''unquenched'' HCN produced from multiphoton photodissociation. Additionally, the information theoretic prior functions

  2. Electron beam inspection of 16nm HP node EUV masks

    NASA Astrophysics Data System (ADS)

    Shimomura, Takeya; Narukawa, Shogo; Abe, Tsukasa; Takikawa, Tadahiko; Hayashi, Naoya; Wang, Fei; Ma, Long; Lin, Chia-Wen; Zhao, Yan; Kuan, Chiyan; Jau, Jack

    2012-11-01

    EUV lithography (EUVL) is the most promising solution for 16nm HP node semiconductor device manufacturing and beyond. The fabrication of defect free EUV mask is one of the most challenging roadblocks to insert EUVL into high volume manufacturing (HVM). To fabricate and assure the defect free EUV masks, electron beam inspection (EBI) tool will be likely the necessary tool since optical mask inspection systems using 193nm and 199nm light are reaching a practical resolution limit around 16nm HP node EUV mask. For production use of EBI, several challenges and potential issues are expected. Firstly, required defect detection sensitivity is quite high. According to ITRS roadmap updated in 2011, the smallest defect size needed to detect is about 18nm for 15nm NAND Flash HP node EUV mask. Secondly, small pixel size is likely required to obtain the high sensitivity. Thus, it might damage Ru capped Mo/Si multilayer due to accumulated high density electron beam bombardments. It also has potential of elevation of nuisance defects and reduction of throughput. These challenges must be solved before inserting EBI system into EUV mask HVM line. In this paper, we share our initial inspection results for 16nm HP node EUV mask (64nm HP absorber pattern on the EUV mask) using an EBI system eXplore® 5400 developed by Hermes Microvision, Inc. (HMI). In particularly, defect detection sensitivity, inspectability and damage to EUV mask were assessed. As conclusions, we found that the EBI system has capability to capture 16nm defects on 64nm absorber pattern EUV mask, satisfying the sensitivity requirement of 15nm NAND Flash HP node EUV mask. Furthermore, we confirmed there is no significant damage to susceptible Ru capped Mo/Si multilayer. We also identified that low throughput and high nuisance defect rate are critical challenges needed to address for the 16nm HP node EUV mask inspection. The high nuisance defect rate could be generated by poor LWR and stitching errors during EB writing

  3. Thin bilayer resists for 193-nm and future photolithography II

    NASA Astrophysics Data System (ADS)

    Hishiro, Yoshi; Hyatt, Michael

    2007-03-01

    Bilayer, Si-containing resists are a technique of interest and a strong candidate to replace chemical vapor deposition (CVD) hardmask processes for small critical dimensions (CDs). Previously, we proposed a very thin film approach using bilayer resists for future lithography, defined the requirements for the resists, and demonstrated 55nm transferred patterns with high aspect ratios using 2-beam interferometer exposure. In this paper, we have demonstrated smaller-than- 60nm transferred patterns with a high numerical aperture (NA) scanner, as well as 45nm and 40nm transferred patterns with a 2-beam system using a 20% Si-containing thin bilayer resist. Immersion scanner exposure and a 35nm CD with 2- beam system were also studied.

  4. Applications of the 308-nm excimer laser in dermatology

    NASA Astrophysics Data System (ADS)

    Farkas, A.; Kemeny, L.

    2006-05-01

    Excimer lasers contain a mixture of a noble inert gas and a halogen, which form excited dimers only in the activated state. High-energy current is used to produce these dimers, which have a very short lifetime, and after their fast dissociation they release the excitation energy through ultraviolet photons. The application of these lasers proved to be successful in medicine, including the field of ophthalmology, cardiology, angiology, dentistry, orthopaedics, and, in recent years, dermatology. For medical purposes, the 193-nm argon fluoride, the 248-nm krypton fluoride, the 351-nm xenon fluoride, and the 308-nm xenon chloride lasers are used. Recently, the 308-nm xenon chloride laser has gained much attention as a very effective treatment modality in dermatological disorders. It was successfully utilized in psoriasis; later, it proved to be useful in handling other lightsensitive skin disorders and even in the treatment of allergic rhinitis. This review summarizes the possible applications of this promising tool in dermatology.

  5. Electric Field-Assisted Photochemical Water Splitting Should Operate with 287 nm Light.

    PubMed

    Bachler, Vinzenz; Gärtner, Wolfgang

    2016-05-01

    The major photoreaction of water is the homolytic splitting of one O-H bond starting from the 1(1) B1 excited state (λmax = 167 nm). This reaction produces H• and •OH radicals. The combination of two H• atoms leads to the potential energy carrier dihydrogen. However, the energy required to obtain the photoreactive 1(1) B1 electronic state is about 7.4 eV, which cannot be effectively provided by solar radiation. The sun light spectrum on earth comprises the visible and ultraviolet region, but shows vanishing intensity near 7 eV (177.1 nm). This work provides theoretical evidence that the photoreactive 1(1) B1 state of water can be shifted into the ultraviolet (UV-B) light region (≈287 nm) by including explicitly an electric field in the calculations of the water absorption spectrum. To accomplish such bathochromic shift, a large field strength of 3.08 VÅ(-1) is required. The field-dependent excitation energies were calculated by applying the symmetry-adapted cluster configuration interaction (SAC-CI) procedure. Based on this theoretical analysis, we propose that photochemical water splitting can be accomplished by means of 287 nm light provided the water molecule is favorably oriented by an external electric field and is subsequently activated by a reversal of the field orientation.

  6. 2-D mapping of skin chromophores in the spectral range 500 - 700 nm.

    PubMed

    Jakovels, Dainis; Spigulis, Janis

    2010-03-01

    The multi-spectral imaging technique has been used for distant mapping of in-vivo skin chromophores by analyzing spectral data at each reflected image pixel and constructing 2-D maps of the relative concentrations of oxy-/deoxy-haemoglobin and melanin. Instead of using a broad visible-NIR spectral range, this study focuses on narrowed spectral band 500-700 nm, speeding-up the signal processing procedure. Regression analysis confirmed that superposition of three Gaussians is optimal analytic approximation for the oxy-haemoglobin absorption tabular spectrum in this spectral band, while superposition of two Gaussians fits well for deoxy-haemoglobin absorption and exponential function - for melanin absorption. The proposed approach was clinically tested for three types of in-vivo skin provocations: ultraviolet irradiance, chemical reaction with vinegar essence and finger arterial occlusion. Spectral range 500-700 nm provided better sensitivity to oxy-haemoglobin changes and higher response stability to melanin than two reduced ranges 500-600 nm and 530-620 nm.

  7. Autocatalysis-driven clock reaction II: kinetics of the pentathionate-periodate reaction.

    PubMed

    Xu, Li; Horváth, Attila K

    2014-10-23

    The pentathionate-periodate reaction has been investigated by spectrophotometrically monitoring the total amount of iodine evolved in the presence of phosphoric acid/dihydrogen phosphate buffer at 468 nm. The majority of the main characteristics of the title system is very reminiscent of that found recently in the pentathionate-iodate reaction, a system that led us to classify generally the clock reactions. Along with the pentathionate-iodate reaction the title system is proposed to belong to the autocatalysis-driven clock reactions as well. The kinetic model of the pentathionate-iodate system published recently was implemented by the necessary reactions of periodate to compose a 24-step kinetic model in which the mechanisms of the pentathionate-iodine, pentathionate-iodate, bisulfite-periodate, bisulfite-iodate, iodide-periodate, and the well-known Dushman reactions are combined. A thorough analysis revealed that the direct pentathionate-periodate reaction plays a role only to produce iodide ion via a finite sequence of reactions, and once its concentration reaches a certain level, the reaction is almost exclusively governed by the pentathionate-iodine, the iodide-periodate, and the Dushman reactions. As expected strong catalytic effect of the buffer composition is also found that can readily be explained by its well-known catalytic influence on the Dushman reaction.

  8. Core level photoionization on free sub-10-nm nanoparticles using synchrotron radiation

    SciTech Connect

    Meinen, Jan; Leisner, Thomas; Khasminskaya, Svetlana; Eritt, Markus; Antonsson, Egill; Langer, Burkhard; Ruehl, Eckart

    2010-08-15

    A novel instrument is presented, which permits studies on singly charged free nanoparticles in the diameter range from 1 to 30 nm using synchrotron radiation in the soft x-ray regime. It consists of a high pressure nanoparticle source, a high efficiency nanoparticle beam inlet, and an electron time-of-flight spectrometer suitable for probing surface and bulk properties of free, levitated nanoparticles. We show results from x-ray photoelectron spectroscopy study near the Si L{sub 3,2}-edge on 8.2 nm SiO{sub 2} particles prepared in a nanoparticle beam. The possible use of this apparatus regarding chemical reactions on the surface of nanometer-sized particles is highlighted. This approach has the potential to be exploited for process studies on heterogeneous atmospheric chemistry.

  9. Biodegradation of 3,3',4,4'-tetrachlorobiphenyl by Sinorhizobium meliloti NM.

    PubMed

    Wang, Xiaomi; Teng, Ying; Luo, Yongming; Dick, Richard P

    2016-02-01

    A rhizobial strain, Sinorhizobium meliloti NM, could use 3,3',4,4'-tetrachloro-biphenyl (PCB 77) as the sole carbon and energy source for growth in mineral salt medium. The degradation efficiency of PCB 77 by strain NM and the bacterial growth increased with a decrease in PCB 77 concentration (5-0.25mgL(-1)). The addition of secondary carbon sources, phenolic acids and one surfactant influenced PCB 77 degradation, rhizobial growth and biofilm formation. The highest degradation efficiency was observed in the presence of caffeic acid. Benzoate and chloride ions were detected as the PCB 77 metabolites. The up-regulation of benzoate metabolism-related gene expression was also observed using quantitative reverse transcription-polymerase chain reaction. This report is the first to demonstrate Sinorhizobium using coplanar tetrachlorobiphenyl as a sole carbon and energy source, indicating the potential wide benefit to the field of rhizobia-assisted bioremediation.

  10. Wavelength dependence on the forensic analysis of glass by nanosecond 266 nm and 1064 nm laser induced breakdown spectroscopy

    SciTech Connect

    Cahoon, Erica M.; Almirall, Jose R.

    2010-05-01

    Laser induced breakdown spectroscopy can be used for the chemical characterization of glass to provide evidence of an association between a fragment found at a crime scene to a source of glass of known origin. Two different laser irradiances, 266 nm and 1064 nm, were used to conduct qualitative and quantitative analysis of glass standards. Single-pulse and double-pulse configurations and lens-to-sample-distance settings were optimized to yield the best laser-glass coupling. Laser energy and acquisition timing delays were also optimized to result in the highest signal-to-noise ratio corresponding to the highest precision and accuracy. The crater morphology was examined and the mass removed was calculated for both the 266 nm and 1064 nm irradiations. The analytical figures of merit suggest that the 266 nm and 1064 nm wavelengths are capable of good performance for the forensic chemical characterization of glass. The results presented here suggest that the 266 nm laser produces a better laser-glass matrix coupling, resulting in a better stoichiometric representation of the glass sample. The 266 nm irradiance is therefore recommended for the forensic analysis and comparison of glass samples.

  11. Variation of cell spreading on TiO2 film modified by 775 nm and 388 nm femtosecond laser irradiation

    NASA Astrophysics Data System (ADS)

    Tsukamoto, M.; Shinonaga, T.; Sato, Y.; Chen, P.; Nagai, A.; Hanawa, T.

    2014-03-01

    Titanium (Ti) is one of the most used biomaterials in metals. However, Ti is typically artificial materials. Thus, it is necessary for improving the biocompatibility of Ti. Recently, coating of the titanium dioxides (TiO2) film on Ti plate has been proposed to improve biocompatibility of Ti. We have developed coating method of the film on Ti plate with an aerosol beam. Periodic structures formation on biomaterials was also a useful method for improving the biocompatibility. Direction of cell spreading might be controlled along the grooves of periodic microstructures. In our previous study, periodic nanostructures were formed on the film by femtosecond laser irradiation at fundamental wave (775 nm). Period of the periodic nanostructures was about 230 nm. In cell test, cell spreading along the grooves of the periodic nanostructures was observed although it was not done for the film without the periodic nanostructures. Then, influence of the period of the periodic nanostructures on cell spreading has not been investigated yet. The period might be changed by changing the laser wavelength. In this study, the periodic nanostructures were created on the film with femtosecond laser at 775nm and 388 nm, respectively. After cell test, cell spreading along the grooves of the periodic nanostructures was observed on 775 nm and 388nm laser irradiated areas. Distribution of direction of cell spreading on laser irradiated area was also examined. These results suggested that controlling the cell spreading on periodic nanostructures with period of 230 nm was better than that with period of 130 nm.

  12. A continuous wave 10 W cryogenic fiber amplifier at 1015 nm and frequency quadrupling to 254 nm.

    PubMed

    Steinborn, R; Koglbauer, A; Bachor, P; Diehl, T; Kolbe, D; Stappel, M; Walz, J

    2013-09-23

    A stable, continuous wave, single frequency fiber amplifier system at 1015 nm with 10 W output power is presented. It is based on a large mode double clad fiber cooled to liquid nitrogen temperature. The amplified light is frequency quadrupled to 254 nm and used for spectroscopy of the 6¹S → 6³P transition in mercury.

  13. Transport of triplet excitons along continuous 100 nm polyfluorene chains

    SciTech Connect

    Xi, Liang; Bird, Matthew; Mauro, Gina; Asaoka, Sadayuki; Cook, Andrew R.; Chen, Hung -Cheng; Miller, John R.

    2014-12-03

    Triplet excitons created in poly-2,7-(9,9-dihexyl)fluorene (pF) chains with end trap groups in solution are efficiently transported to and captured by the end groups. The triplets explore the entire lengths of the chains, even for ~100 nm long chains enabling determination of the completeness of end capping. The results show that the chains continuous: they may contain transient barriers or traps, such as those from fluctuations of dihedral angles, but are free of major defects that stop motion of the triplets. Quantitative determinations are aided by the addition of a strong electron donor, TMPD, which removes absorption bands of the end-trapped triplets. For chains having at least one end trap, triplet capture is quantitative on the 1 µs timescale imposed by the use of the donor. Fractions of chains having no end traps were 0.15 for pF samples with anthraquinone (AQ) end traps and 0.063 with naphthylimide (NI) end traps. These determinations agreed with measurements by NMR for short (<40 polymer repeat units (PRU)) chains, where NMR determinations are accurate. The results find no evidence for traps or barriers to transport of triplets, and places limits on the possible presence of defects as impenetrable barriers to less than one per 300 PRU. The present results present a paradigm different from the current consensus, derived from observations of singlet excitons, that conjugated chains are divided into “segments,” perhaps by some kind of defects. For the present pF chains, the segmentation either does not apply to triplet excitons or is transient so that the defects are healed or surmounted in times much shorter than 1 µs. Triplets on chains without end trap groups transfer to chains with end traps on a slower time scale. Rate constants for these bimolecular triplet transfer reactions were found to increase with the length of the accepting chain, as did rate constants for triplet transfer to the chains from small molecules like biphenyl. As a result, a

  14. Transport of triplet excitons along continuous 100 nm polyfluorene chains

    DOE PAGES

    Xi, Liang; Bird, Matthew; Mauro, Gina; ...

    2014-12-03

    Triplet excitons created in poly-2,7-(9,9-dihexyl)fluorene (pF) chains with end trap groups in solution are efficiently transported to and captured by the end groups. The triplets explore the entire lengths of the chains, even for ~100 nm long chains enabling determination of the completeness of end capping. The results show that the chains continuous: they may contain transient barriers or traps, such as those from fluctuations of dihedral angles, but are free of major defects that stop motion of the triplets. Quantitative determinations are aided by the addition of a strong electron donor, TMPD, which removes absorption bands of the end-trappedmore » triplets. For chains having at least one end trap, triplet capture is quantitative on the 1 µs timescale imposed by the use of the donor. Fractions of chains having no end traps were 0.15 for pF samples with anthraquinone (AQ) end traps and 0.063 with naphthylimide (NI) end traps. These determinations agreed with measurements by NMR for short (<40 polymer repeat units (PRU)) chains, where NMR determinations are accurate. The results find no evidence for traps or barriers to transport of triplets, and places limits on the possible presence of defects as impenetrable barriers to less than one per 300 PRU. The present results present a paradigm different from the current consensus, derived from observations of singlet excitons, that conjugated chains are divided into “segments,” perhaps by some kind of defects. For the present pF chains, the segmentation either does not apply to triplet excitons or is transient so that the defects are healed or surmounted in times much shorter than 1 µs. Triplets on chains without end trap groups transfer to chains with end traps on a slower time scale. Rate constants for these bimolecular triplet transfer reactions were found to increase with the length of the accepting chain, as did rate constants for triplet transfer to the chains from small molecules like biphenyl. As a

  15. Gain-switched 311-nm Ti:Sapphire laser might be a potential treatment modality for atopic dermatitis.

    PubMed

    Choi, Sun Young; Oh, Chang Taek; Kwon, Tae-Rin; Kwon, Hyun Jung; Choi, Eun Ja; Jang, Yu-Jin; Kim, Hye Sung; Chu, Hong; Mun, Seog Kyun; Kim, Myeung Nam; Kim, Beom Joon

    2016-09-01

    Phototherapy with 311-nm narrowband-UVB (NBUVB) is an effective adjuvant treatment modality for atopic dermatitis (AD). In this study, we evaluated the therapeutic effect of the newly developed gain-switched 311-nm Ti:Sapphire laser device using a NC/Nga mouse AD model. A total number of 50 mice were used in this study. Atopic dermatitis (AD) was induced in mice by exposure to Dermatophagoides farina. These, NC/Nga mice were then treated with conventional 311-nm NBUVB or the newly developed gain-switched 311-nm Ti:Sapphire laser. The clinical features, dermatitis severity scores, and scratching behavior were assessed. In addition, serologic analyses including inflammatory cytokines and histological analyses were performed. Gain-switched 311-nm Ti:Sapphire laser improved the AD-like skin lesions, severity, and symptoms of AD in the NC/Nga mouse model. This new laser also modulated the immune response found in the AD model, including hyper-IgE, upregulated Th2 cytokines, and the Th2-mediated allergic inflammatory reaction. Gain-switched 311-nm Ti:Sapphire laser shows therapeutic promise via an immune-modulation mechanism in an AD mouse model. These data suggest that gain-switched 311-nm Ti:Sapphire laser may be useful as a targeted phototherapy modality for AD.

  16. EUV reticle inspection with a 193nm reticle inspector

    NASA Astrophysics Data System (ADS)

    Broadbent, William; Inderhees, Gregg; Yamamoto, Tetsuya; Lee, Isaac; Lim, Phillip

    2013-06-01

    The prevailing industry opinion is that EUV Lithography (EUVL) will enter High Volume Manufacturing (HVM) in the 2015 - 2017 timeframe at the 16nm HP node. Every year the industry assesses the key risk factors for introducing EUVL into HVM - blank and reticle defects are among the top items. To reduce EUV blank and reticle defect levels, high sensitivity inspection is needed. To address this EUV inspection need, KLA-Tencor first developed EUV blank inspection and EUV reticle inspection capability for their 193nm wavelength reticle inspection system - the Teron 610 Series (2010). This system has become the industry standard for 22nm / 3xhp optical reticle HVM along with 14nm / 2xhp optical pilot production; it is further widely used for EUV blank and reticle inspection in R and D. To prepare for the upcoming 10nm / 1xhp generation, KLA-Tencor has developed the Teron 630 Series reticle inspection system which includes many technical advances; these advances can be applied to both EUV and optical reticles. The advanced capabilities are described in this paper with application to EUV die-to-database and die-to-die inspection for currently available 14nm / 2xhp generation EUV reticles. As 10nm / 1xhp generation optical and EUV reticles become available later in 2013, the system will be tested to identify areas for further improvement with the goal to be ready for pilot lines in early 2015.

  17. Sub-30-nm defect removal on EUV substrates

    NASA Astrophysics Data System (ADS)

    Rastegar, Abbas; Eichenlaub, Sean; Kadaksham, Arun John; House, Matt; Cha, Brian; Yun, Henry

    2009-01-01

    Naturally occurring sub 30 nm defects on quartz and Low Thermal Expansion Material (LTEM) substrates were characterized by using Atomic Force Microscope(AFM). Our data indicates that a majority of defects on the incoming substrate are hard defects including large, flat particles with a height less than 5 nm, tiny particles with a size of 10 nm to 30 nm SEVD and pits with a depth of about 9 nm. All the soft particles added by handling with sizes of >50 nm can be removed with a single cleaning process. At least four cleaning cycles are required to remove all of the remaining embedded particles. However, after particle removal in their initial location a shallow pit remains. Based on detailed characterization of defect and surface by AFM, we propose that these hard particles are added during the glass polishing step and therefore it is important to revisit the glass Chemical Mechanical Polishing (CMP) processes and optimize them for defect reduction. A qualitative value for particle removal efficiency (PRE) of >99% was obtained for 20 nm Poly Styrene Latex Sphere (PSL) deposited particles on surface of glass.

  18. Photomask technology for 32nm node and beyond

    NASA Astrophysics Data System (ADS)

    Hikichi, Ryugo; Ishii, Hiroyuki; Migita, Hidekazu; Kakehi, Noriko; Shimizu, Mochihiro; Takamizawa, Hideyoshi; Nagano, Tsugumi; Hashimoto, Masahiro; Iwashita, Hiroyuki; Suzuki, Toshiyuki; Hosoya, Morio; Ohkubo, Yasushi; Ushida, Masao; Mitsui, Hideaki

    2008-05-01

    193nm-immersion lithography is the most promising technology for 32nm-node device fabrication. At the 32nm technology-node, the performance of photomasks, not only phase-shift masks but also binary masks, needs to be improved, especially in "resolution" and "CD accuracy". To meet sub-100nm resolution with high precision, further thinning of resist thickness will be needed. To improve CD performance, we have designed a new Cr-on-glass (COG) blank for binary applications, having OD-3 at 193nm. This simple Cr structure can obtain superior performance with the conventional mask-making process. Since the hardmask concept is one of the alternative solutions, we have also designed a multilayered binary blank. The new COG blank (NTARC) was fully dry-etched with over 25% shorter etching time than NTAR7, which is a conventional COG blank. Thinner resist (up to 200nm) was possible for NTARC. NTARC with 200nm-thick resist showed superior resolution and CD linearity in all pattern categories. On the other hand, the multilayered binary stack gives us a wide etching margin for several etching steps. Super thin resist (up to 100nm) was suitable by using a Cr-hardmask on a MoSi-absorber structure (COMS). The COMS blanks showed superior performance, especially in tiny clear patterns, such as the isolated hole pattern. We confirmed that these new photomask blanks, NTARC and COMS, will meet the requirements for 32nm-node and beyond, for all aspects of mask-making.

  19. Response of Cloud Condensation Nuclei (> 50 nm) to changes in ion-nucleation

    NASA Astrophysics Data System (ADS)

    Pedersen, J. O.; Enghoff, M. B.; Svensmark, H.

    2012-12-01

    The role of ionization in the formation of clouds and aerosols has been debated for many years. A body of evidence exists that correlates cloud properties to galactic cosmic ray ionization; however these results are still contested. In recent years experimental evidence has also been produced showing that ionization can promote the nucleation of small aerosols at atmospheric conditions. The experiments showed that an increase in ionization leads to an increase in the formation of ultrafine aerosols (~3 nm), but in the real atmosphere such small particles have to grow by coagulation and condensation to become cloud condensation nuclei (CCN) in order to have an effect on clouds. However, numerical studies predict that variations in the count of ultra-fine aerosols will lead only to an insignificant change in the count of CCN. This is due to 1) the competition between the additional ultra-fine aerosols for the limited supply of condensable gases leading to a slower growth and 2) the increased loss rates of the additional particles during the longer growth-time. We investigated the growth of aerosols to CCN sizes using an 8 m3 reaction chamber made from electro-polished stainless steel. One side was fitted with a Teflon foil to allow ultraviolet light to illuminate the chamber, which was continuously flushed with dry purified air. Variable concentrations of water vapor, ozone, and sulfur dioxide could be added to the chamber. UV-lamps initiated photochemistry producing sulfuric acid. Ionization could be enhanced with two Cs-137 gamma sources (30 MBq), mounted on each side of the chamber. Figure 1 shows the evolution of the aerosols, following a nucleation event induced by the gamma sources. Previous to the event the aerosols were in steady state. Each curve represents a size bin: 3-10 nm (dark purple), 10-20 nm (purple), 20-30 nm (blue), 30-40 nm (light blue), 40-50 nm (green), 50-60 nm (yellow), and 60-68 nm (red). Black curves show a ~1 hour smoothing. The initial

  20. EUV mask inspection study for sub-20nm device

    NASA Astrophysics Data System (ADS)

    Shin, Inkyun; Yoon, Gisung; Na, Ji Hoon; Chung, Paul D. H.; Jeon, Chan-Uk

    2012-11-01

    Reflected light inspection has been used to inspect EUVL mask which consists of multi layers and metal absorber. However, sub-wavelength half pitch patterns and reflected inspection make unprecedented phenomenon like tone inversion. These lead EUV inspection more difficult in detectability and inspectability for separating out defects and false. In this study, we report the evaluation result of inspection dependency of illumination conditions like OAI(Off-Axis Illumination), sigma and polarization for sub-20nm EUVL PDM(programmed defect mask). With inspection of sub- 20nm device mask, we finally address the inspection feasibility for sub-20nm device and the future direction of inspection technology.

  1. 80 nm tunable DBR-free semiconductor disk laser

    NASA Astrophysics Data System (ADS)

    Yang, Z.; Albrecht, A. R.; Cederberg, J. G.; Sheik-Bahae, M.

    2016-07-01

    We report a widely tunable optically pumped distributed Bragg reflector (DBR)-free semiconductor disk laser with 6 W continuous wave output power near 1055 nm when using a 2% output coupler. Using only high reflecting mirrors, the lasing wavelength is centered at 1034 nm and can be tuned up to a record 80 nm by using a birefringent filter. We attribute such wide tunability to the unique broad effective gain bandwidth of DBR-free semiconductor disk lasers achieved by eliminating the active mirror geometry.

  2. High-Performance 1645-nm Er: YAG Laser

    DTIC Science & Technology

    2007-09-25

    laser set-up is shown in Figure 1. An IPG Photonics TEM00 erbium fiber laser , which provided 20 W cw power at 1532.4 nm, was used in these experi...output of the resonantly fiber - laser -pumped Er:AYG laser at 1645 nm using 0.25% doped crystal out- performed the 0.5% doped crystal. In addition to the...the advantages of small quantum defect and small thermal load for the laser materials. High-brightness erbium fiber pump lasers at 1532 nm not only

  3. Partially Oxidized Sub-10 nm MnO Nanocrystals with High Activity for Water Oxidation Catalysis

    PubMed Central

    Jin, Kyoungsuk; Chu, Arim; Park, Jimin; Jeong, Donghyuk; Jerng, Sung Eun; Sim, Uk; Jeong, Hui-Yun; Lee, Chan Woo; Park, Yong-Sun; Yang, Ki Dong; Kumar Pradhan, Gajendra; Kim, Donghun; Sung, Nark-Eon; Hee Kim, Sun; Nam, Ki Tae

    2015-01-01

    The oxygen evolution reaction (OER) is considered a major bottleneck in the overall water electrolysis process. In this work, highly active manganese oxide nano-catalysts were synthesized via hot injection. Facile surface treatment generated Mn(III) species on monodisperse 10 nm MnO nanocrystals (NCs). Size dependency of MnO NCs on OER activity was also investigated. Surprisingly, the partially oxidized MnO NCs only required 530 mV @ 5 mA cm−2 under near neutral conditions. PMID:25998696

  4. Influence of humidity on photochemical ozone generation with 172nm xenon excimer lamps

    NASA Astrophysics Data System (ADS)

    Salvermoser, M. J.; Kogelschatz, U.; Murnick, D. E.

    2009-08-01

    The reaction kinetics of photochemical ozone (O{3}) generation in humid air and oxygen (O{2}) using efficient, narrow band vacuum ultra violet (VUV) 172 nm xenon excimer lamps is discussed. Trace amounts of water (H{2}O) vapor in the process gas leads to hydroxyl (OH) and hydroperoxy (HO{2}) radical formation. These radicals drive a catalytic O{3} destruction cycle limiting O{3} saturation concentration. This catalytic O{3} destruction cycle was included into a quantitative kinetic model describing photochemical O{3} production. Experimental O{3} saturation concentrations obtained with coaxial VUV driven photochemical O{3} generators compare satisfactorily with the models predictions.

  5. Grafting onto poly(ethylene terephthalate) driven by 172 nm UV light

    NASA Astrophysics Data System (ADS)

    Zhu, Zhengmao; Kelley, Michael J.

    2005-10-01

    The reactivity of the surface of poly(ethylene terephthalate) (PET) film under 172 nm UV irradiation (xenon excimer lamp) towards nitrogen-borne 1-octene, n-nonane and heptafluorodecene vapor was investigated. Materials receiving from 0 to 24 J/cm 2 of UV were examined by X-ray photoelectron spectroscopy (XPS), time of flight secondary ion mass spectroscopy (ToF/SIMS), water and mineral oil contact angle measurement and atomic force microscopy (AFM). A uniform nanoscale layer developed on PET surface attributed to the grafting reaction between photolytically-produced polymer radicals and vapor phase molecules.

  6. Catalysis of Photochemical Reactions.

    ERIC Educational Resources Information Center

    Albini, A.

    1986-01-01

    Offers a classification system of catalytic effects in photochemical reactions, contrasting characteristic properties of photochemical and thermal reactions. Discusses catalysis and sensitization, examples of catalyzed reactions of excepted states, complexing ground state substrates, and catalysis of primary photoproducts. (JM)

  7. Anaphylaxis-Like Reactions

    MedlinePlus

    ... Home Conditions Anaphylaxis Anaphylaxis-Like Reactions Anaphylaxis-Like Reactions Make an Appointment Refer a Patient Ask a ... exposed to a foreign substance, some people suffer reactions identical to anaphylaxis, but no allergy (IgE antibody) ...

  8. Efficient laser operation of Nd3+:Lu2O3 at various wavelengths between 917 nm and 1463 nm

    NASA Astrophysics Data System (ADS)

    von Brunn, P.; Heuer, A. M.; Fornasiero, L.; Huber, G.; Kränkel, C.

    2016-08-01

    Even though the first Nd3+-doped sesquioxide lasers have been realized more than 50 years ago, up to now no reports on efficient laser operation of Nd3+:doped sesquioxides can be found. In this work, we review the favorable spectroscopic properties of the sesquioxide Nd3+:Lu2O3 in terms of ground state absorption, stimulated emission, and excited state absorption cross sections as well as the upper level lifetime. Making use of these properties, we achieved efficient laser performance on eight different laser transitions in the wavelength range between 917 nm and 1463 nm under Ti:sapphire laser pumping using state-of-the-art HEM-grown Nd3+:Lu2O3 crystals with good optical quality. At the strongest transition around 1076 nm we determined a slope efficiency of 69%, which represents the highest efficiency ever obtained for a Nd3+-doped sesquioxide. Furthermore, we could generate watt level output powers and high slope efficiencies for seven other transitions. Lasers at 917 nm, 1053 nm, 1108 nm and 1463 nm were realized for the first time and the latter represents one of the longest laser wavelengths obtained on the 4F3/2  →  4I13/2 transition in Nd3+-doped materials.

  9. 76 FR 76801 - New Mexico Disaster #NM-00024

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-08

    ... Mexico Disaster NM-00024 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a... New Mexico (FEMA- 4047-DR), dated 11/23/2011. Incident: Flooding. Incident Period: 08/19/2011...

  10. Diffuse optical spectroscopy of breast tissue extended to 1100 nm

    NASA Astrophysics Data System (ADS)

    Taroni, Paola; Bassi, Andrea; Comelli, Daniela; Farina, Andrea; Cubeddu, Rinaldo; Pifferi, Antonio

    2009-09-01

    The feasibility of in vivo measurements in the range of 1000 to 1100 nm and the potential benefits of operation in that wavelength range for diagnostic applications are investigated. To this purpose, an existing system for time-resolved diffuse spectroscopy is modified to enable in vivo studies to be carried out continuously from 600 to 1100 nm. The optical characterization of collagen powder is extended to 1100 nm and an accurate measurement of the absorption properties of lipid is carried out over the entire spectral range. Finally, the first in vivo absorption and scattering spectra of breast tissue are measured from 10 healthy volunteers between 600 and 1100 nm and tissue composition is evaluated in terms of blood parameters and water, lipid, and collagen content using a spectrally constrained global fitting procedure.

  11. Compact frequency-quadrupled pulsed 1030nm fiber laser

    NASA Astrophysics Data System (ADS)

    McIntosh, Chris; Goldberg, Lew; Cole, Brian; DiLazaro, Tom; Hays, Alan D.

    2016-03-01

    A compact 1030nm fiber laser for ultraviolet generation at 257.5nm is presented. The laser employs a short length of highly-doped, large core (20μm), coiled polarization-maintaining ytterbium-doped double-clad fiber pumped by a wavelength-stabilized 975nm diode. It is passively Q-switched via a Cr4+:YAG saturable absorber and generates 2.4W at 1030nm in a 110μJ pulse train. Lithium triborate (LBO) and beta-barium borate (BBO) are used to achieve 325mW average power at the fourth harmonic. The laser's small form factor, narrow linewidth and modest power consumption are suitable for use in a man-portable ultraviolet Raman explosives detection system.

  12. RadNet Air Data From Navajo Lake, NM

    EPA Pesticide Factsheets

    This page presents radiation air monitoring and air filter analysis data for Navajo Lake, NM from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  13. RadNet Air Data From Albuquerque, NM

    EPA Pesticide Factsheets

    This page presents radiation air monitoring and air filter analysis data for Albuquerque, NM from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  14. RadNet Air Data From Carlsbad, NM

    EPA Pesticide Factsheets

    This page presents radiation air monitoring and air filter analysis data for Carlsbad, NM from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  15. The Missing Solar Irradiance Spectrum: 1 to 7 nm

    NASA Astrophysics Data System (ADS)

    Sojka, J. J.; Lewis, M.; David, M.; Schunk, R. W.; Woods, T. N.; Eparvier, F. G.; Warren, H. P.

    2015-12-01

    During large X-class flares the Earth's upper atmospheric E-region responds immediately to solar photons in the 1 to 7 nm range. The response can change the E-region density by factors approaching 10, create large changes in conductivity, and plague HF communications. GOES-XRS provide 0.1 to 0.8 nm and a 0.05 to 0.4 nm integral channels; SOHO-SEM provided a 0 to 50 nm irradiance; TIMED and SORCE-XPS diode measurements also integrated down to 0.1 nm; and most recently SDO-EVE provided a 0.1 to 7 nm irradiance. For atmospheric response to solar flares the cadence is also crucial. Both GOES and SDO provided integral measurements at 10 seconds or better. Unfortunately these measurements have failed to capture the 1 to 7 nm spectral changes that occur during flares. It is these spectral changes that create the major impact since the ionization cross-section of the dominant atmospheric species, N2 and O2, both contain step function changes in the cross-sections. Models of the solar irradiance over this critical wavelength regime have suffered from the need to model the spectral variability based on incomplete measurements. The most sophisticated empirical model FISM [Chamberlin et al., 2008] used 1 nm spectral binning and various implementations of the above integral measurements to describe the 1 to 7 nm irradiance. Since excellent solar observations exist at other wavelengths it is possible to construct an empirical model of the solar atmosphere and then use this model to infer the spectral distribution at wavelengths below 5 nm. This differential emission measure approach has been used successfully in other contexts [e.g., Warren, 2005, Chamberlin et al., 2009]. This paper contrasts the broadband versus spectrally resolved descriptions of the incoming irradiance that affects the upper atmospheric E-layer. The results provide a prescription of what wavelength resolution would be needed to adequately measure the incoming solar irradiance in the 1 to 7 nm range.

  16. Picosecond holmium fibre laser pumped at 1125 \\ {\\text{nm}}

    NASA Astrophysics Data System (ADS)

    Kamynin, V. A.; Filatova, S. A.; Zhluktova, I. V.; Tsvetkov, V. B.

    2016-12-01

    We report a passively mode-locked, all-fibre holmium laser based on nonlinear polarisation rotation. As a pump source use is made of an 1125-{\\text{nm}} ytterbium-doped fibre laser. The pulse repetition rate of the holmium laser is 7.5 {\\text{MHz}}, and the pulse duration does not exceed 52 {\\text{ps}} at wavelengths of 2065 and 2080 {\\text{nm}}. The average laser output power reaches 5 {\\text{mW}}.

  17. Investigation of a Pulsed 1550 nm Fiber Laser System

    DTIC Science & Technology

    2015-12-15

    Jain 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT...14. ABSTRACT There is a strong need for a pulsed laser system at eye safe wavelengths for illuminator applications . High power pulsed 1550 nm fiber...system at eye safe wavelengths for illuminator applications . High power pulsed 1550 nm fiber lasers systems are able to generate, shaped, pulses at

  18. Cs 728 nm Laser Spectroscopy and Faraday Atomic Filter

    NASA Astrophysics Data System (ADS)

    Liu, Zhong-Zheng; Tao, Zhi-Ming; Jiang, Zhao-Jie; Chen, Jing-Biao

    2014-12-01

    We mainly present the 728 nm laser spectroscopy and Faraday atomic filter of Cs atoms with 650 MHz linewidth and 2.6% transmission based on an electrodeless discharge vapor lamp, compared with Rb 728 nm laser spectroscopy. Accidentally, this remarkably strong Cs 728 nm transition from the 6F7/2 state to the 5D5/2 state is only about 2.5 GHz away from the Rb 728 nm transition of the future potential four-level active optical clock, once laser cooled and trapped from the 7S1/2 state to the 5P1/2 state, as we proposed previously. A Faraday atomic filter stabilized 728 nm laser using a Cs electrodeless discharge vapor lamp with a power of 10mW will provide a frequency reference to evaluate the performance of the potential Rb four-level active optical clock at 728 nm with power less than 1 nW by 2.5 GHz heterodyne measurements.

  19. Electron beam inspection methods for imprint lithography at 32 nm

    NASA Astrophysics Data System (ADS)

    Selinidis, Kosta; Thompson, Ecron; Sreenivasan, S. V.; Resnick, Douglas J.

    2009-01-01

    Step and Flash Imprint Lithography redefines nanoimprinting. This novel technique involves the field-by-field deposition and exposure of a low viscosity resist deposited by jetting technology onto the substrate. The patterned mask is lowered into the fluid which then quickly flows into the relief patterns in the mask by capillary action. Following this filling step, the resist is crosslinked under UV radiation, and then the mask is removed leaving a patterned solid on the substrate. Compatibility with existing CMOS processes requires a mask infrastructure in which resolution, inspection and repair are all addressed. The purpose of this paper is to understand the limitations of inspection at half pitches of 32 nm and below. A 32 nm programmed defect mask was fabricated. Patterns included in the mask consisted of an SRAM Metal 1 cell, dense lines, and dense arrays of pillars. Programmed defect sizes started at 4 nm and increased to 48 nm in increments of 4 nm. Defects in both the mask and imprinted wafers were characterized scanning electron microscopy and the measured defect areas were calculated. These defects were then inspected using a KLA-T eS35 electron beam wafer inspection system. Defect sizes as small as 12 nm were detected, and detection limits were found to be a function of defect type.

  20. Defect inspection of imprinted 32 nm half pitch patterns

    NASA Astrophysics Data System (ADS)

    Selinidis, Kosta; Thompson, Ecron; McMackin, Ian; Perez, Joseph; Sreenivasan, S. V.; Resnick, Douglas J.

    2008-10-01

    Step and Flash Imprint Lithography redefines nanoimprinting. This novel technique involves the field-by-field deposition and exposure of a low viscosity resist deposited by jetting technology onto the substrate. The patterned mask is lowered into the fluid which then quickly flows into the relief patterns in the mask by capillary action. Following this filling step, the resist is crosslinked under UV radiation, and then the mask is removed leaving a patterned solid on the substrate. Compatibility with existing CMOS processes requires a mask infrastructure in which resolution, inspection and repair are all addressed. The purpose of this paper is to understand the limitations of inspection at half pitches of 32 nm and below. A 32 nm programmed defect mask was fabricated. Patterns included in the mask consisted of an SRAM Metal 1 cell, dense lines, and dense arrays of pillars. Programmed defect sizes started at 4 nm and increased to 48 nm in increments of 4 nm. Defects in both the mask and imprinted wafers were characterized scanning electron microscopy and the measured defect areas were calculated. These defects were then inspected using a KLA-T eS35 electron beam wafer inspection system. Defect sizes as small as 12 nm were detected, and detection limits were found to be a function of defect type.

  1. Power scaling of laser diode pumped Pr3+:LiYF4 cw lasers: efficient laser operation at 522.6 nm, 545.9 nm, 607.2 nm, and 639.5 nm.

    PubMed

    Gün, Teoman; Metz, Philip; Huber, Günter

    2011-03-15

    We report efficient cw laser operation of laser diode pumped Pr(3+)-doped LiYF4 crystals in the visible spectral region. Using two InGaN laser diodes emitting at λ(P)=443.9 nm with maximum output power of 1 W each and a 2.9-mm-long crystal with a doping concentration of 0.5%, output powers of 938 mW, 418 mW, 384 mW, and 773 mW were achieved for the laser wavelengths 639.5 nm, 607.2 nm, 545.9 nm, and 522.6 nm, respectively. The maximum absorbed pump powers were approximately 1.5 W, resulting in slope efficiencies of 63.6%, 32.0%, 52.1%, and 61.5%, as well as electro-optical efficiencies of 9.4%, 4.2%, 3.8%, and 7.7%, respectively. Within these experiments, laser diode-pumped laser action at 545.9 nm was demonstrated for what is believed to be the first time.

  2. Trends in nanosecond melanosome microcavitation up to 1540 nm

    NASA Astrophysics Data System (ADS)

    Schmidt, Morgan S.; Kennedy, Paul K.; Noojin, Gary D.; Vincelette, Rebecca L.; Thomas, Robert J.; Rockwell, Benjamin A.

    2015-09-01

    Thresholds for microcavitation of bovine and porcine melanosomes were previously reported, using single nanosecond (ns) laser pulses in the visible (532 nm) and the near-infrared (NIR) from 1000 to 1319 nm. Here, we report average radiant exposure thresholds for bovine melanosome microcavitation at additional NIR wavelengths up to 1540 nm, which range from ˜0.159 J/cm2 at 800 nm to 4.5 J/cm2 at 1540 nm. Melanosome absorption coefficients were also estimated, and decreased with increasing wavelength. These values were compared to retinal pigment epithelium coefficients, and to water absorption, over the same wavelength range. Corneal total intraocular energy retinal damage threshold values were estimated and compared to the previous (2007) and recently changed (2014) maximum permissible exposure (MPE) safe levels. Results provide additional data that support the recent changes to the MPE levels, as well as the first microcavitation data at 1540 nm, a wavelength for which melanosome microcavitation may be an ns-pulse skin damage mechanism.

  3. Magneto-optical trap for metastable helium at 389 nm

    SciTech Connect

    Koelemeij, J.C.J.; Stas, R.J.W.; Hogervorst, W.; Vassen, W.

    2003-05-01

    We have constructed a magneto-optical trap (MOT) for metastable triplet helium atoms utilizing the 2 {sup 3}S{sub 1}{yields}3 {sup 3}P{sub 2} line at 389 nm as the trapping and cooling transition. The far-red-detuned MOT (detuning {delta}=-41 MHz) typically contains few times 10{sup 7} atoms at a relatively high ({approx}10{sup 9} cm{sup -3}) density, which is a consequence of the large momentum transfer per photon at 389 nm and a small two-body loss rate coefficient (2x10{sup -10} cm{sup 3}/s<{beta}<1.0x10{sup -9} cm{sup 3}/s). The two-body loss rate is more than five times smaller than in a MOT on the commonly used 2 {sup 3}S{sub 1}{yields}2 {sup 3}P{sub 2} line at 1083 nm. Furthermore, laser cooling at 389 nm results in temperatures somewhat lower than those achieved using 1083 nm. The 389-nm MOT exhibits small losses due to two-photon ionization, which have been investigated as well.

  4. Generation and biological evaluation of the products formed from the exposure of Phenothiazine to a 266nm laser beam

    NASA Astrophysics Data System (ADS)

    Alexandru, T.; Pascu, M. L.; Danko, B.; Nastasa, V.; Boni, M.; Militaru, A.; Andrei, I. R.; Staicu, A.; Hunyadi, A.; Armada, A.; Viveiros, M.; Amaral, L.

    2013-06-01

    Phenothiazine exposed to white light or UV radiation undergoes a variety of reactions that result in the degradation of the parental compound and the formation of new species. Chlorpromazine exposed to the 266 nm laser beam of given energy levels yielded species derived from it, whose number increased with the exposure duration. At distinct time intervals the irradiation products were evaluated by spectrophotometry between 200-1500 nm, Thin Layer Chromatography, and for antimicrobial activity of Chlorpromazine against different test organisms such as Staphylococcus aureus.

  5. Preparation of spherical and uniform-sized ferrite nanoparticles with diameters between 50 and 150 nm for biomedical applications

    NASA Astrophysics Data System (ADS)

    Tanaka, Toshiyuki; Shimazu, Ryuichi; Nagai, Hironori; Tada, Masaru; Nakagawa, Takashi; Sandhu, Adarsh; Handa, Hiroshi; Abe, Masanori

    2009-05-01

    Spherical uniform-sized iron ferrite nanoparticles were synthesized by adding a disaccharide and seed ferrite crystals into an aqueous reaction solution. The average size range 50-150 nm was controlled by choosing one out of five disaccharides and by changing the amount of the seed crystals. The particles had a saturation magnetization and a crystalline structure which are similar to those of intermediate Fe 3O 4-γ-Fe 2O 3. When coated with citrate, the particles with nearly 100 nm diameter were stably suspended in water for 2 days. These novel particles will be utilized as magnetic carriers in biomedical applications.

  6. The Spectrum of Th-Ar Hollow Cathode Lamps in the 691nm to 5804nm region Database

    National Institute of Standards and Technology Data Gateway

    SRD 161 The Spectrum of Th-Ar Hollow Cathode Lamps in the 691nm to 5804nm region Database (Web, free access)   This atlas presents observations of the infra-red (IR) spectrum of a low current Th-Ar hollow cathode lamp with the 2-m Fourier transform spectrometer (FTS) at NIST. These observations establish more than 2400 lines that are suitable for use as wavelength standards in the range 691 nm to 5804 nm. The observations were made in collaboration with the European Southern Observatory (ESO), in order to provide calibration reference data for new high-resolution Echelle spectrographs, such as the Cryogenic High-Resolution IR Echelle Spectrograph ([CRIRES]), ESO's new IR spectrograph at the Very Large Telescope in Chile.

  7. 750 nm 1.5 W frequency-doubled semiconductor disk laser with a 44 nm tuning range.

    PubMed

    Saarinen, Esa J; Lyytikäinen, Jari; Ranta, Sanna; Rantamäki, Antti; Sirbu, Alexei; Iakovlev, Vladimir; Kapon, Eli; Okhotnikov, Oleg G

    2015-10-01

    We demonstrate 1.5 W of output power at the wavelength of 750 nm by intracavity frequency doubling a wafer-fused semiconductor disk laser diode-pumped at 980 nm. An optical-to-optical efficiency of 8.3% was achieved using a bismuth borate crystal. The wavelength of the doubled emission could be tuned from 720 to 764 nm with an intracavity birefringent plate. The beam quality parameter M2 of the laser output was measured to be below 1.5 at all pump powers. The laser is a promising tool for biomedical applications that can take advantage of the large penetration depth of light in tissue in the 700-800 nm spectral range.

  8. Orthogonally polarized dual-wavelength Nd:LuVO4 laser at 1086 nm and 1089 nm.

    PubMed

    Huang, Y P; Cho, C Y; Huang, Y J; Chen, Y F

    2012-02-27

    A comparison between the fluorescence spectra of the Nd-doped vanadate crystals (Nd:YVO4, Nd:GdVO4, Nd:LuVO4) for the 4F3/2 → 4I11/2 transition is studied. We numerically analyze the condition of gain-to-loss balance via an uncoated intracavity etalon to achieve the dual-wavelength operation. We further experimentally demonstrate the orthogonally polarized dual-wavelength laser with a single Nd:LuVO4 crystal. The simultaneous dual-wavelength Nd:LuVO4 laser at 1085.7 nm in σ polarization and 1088.5 nm in π polarization is realized. At an incident pump power of 12 W, the average output power obtained at 1085.7 nm and 1088.5 nm is 0.4 W and 1.7 W, respectively.

  9. Compact Fiber Laser for 589nm Laser Guide Star Generation

    NASA Astrophysics Data System (ADS)

    Pennington, D.; Drobshoff, D.; Mitchell, S.; Brown, A.

    Laser guide stars are crucial to the broad use of astronomical adaptive optics, because they facilitate access to a large fraction of possible locations on the sky. Lasers tuned to the 589 nm atomic sodium resonance can create an artificial beacon at altitudes of 95-105 km, thus coming close to reproducing the light path of starlight. The deployment of multiconjugate adaptive optics on large aperture telescopes world-wide will require the use of three to nine sodium laser guide stars in order to achieve uniform correction over the aperture with a high Strehl value. Current estimates place the minimum required laser power at > 10 W per laser for a continuous wave source, though a pulsed format, nominally 6?s in length at ~ 16.7 kHz, is currently preferred as it would enable tracking the laser through the Na layer to mitigate spot elongation. The lasers also need to be compact, efficient, robust and turnkey. We are developing an all-fiber laser system for generating a 589 nm source for laser-guided adaptive optics. Fiber lasers are more compact and insensitive to alignment than their bulk laser counterparts, and the heat-dissipation characteristics of fibers, coupled with the high efficiencies demonstrated and excellent spatial mode characteristics, make them a preferred candidate for many high power applications. Our design is based on sum-frequency mixing an Er/Yb:doped fiber laser operating at 1583 nm with a 938 nm Nd:silica fiber laser in a periodically poled crystal to generate 589 nm. We have demonstrated 14 W at 1583 nm with an Er/Yb:doped fiber laser, based on a Koheras single frequency fiber oscillator amplified in an IPG Photonics fiber amplifier. The Nd:silica fiber laser is a somewhat more novel device, since the Nd3+ ions must operate on the resonance transition (i.e. 4F3/2-4I9/2), while suppressing ASE losses at the more conventional 1088 nm transition. Optimization of the ratio of the fiber core and cladding permits operation of the laser at room

  10. Generation of Thermospheric OI 845 nm Emission by Bowen Fluorescence

    NASA Astrophysics Data System (ADS)

    Huestis, D. L.; Sharpee, B. D.; Cosby, P. C.; Slanger, T. G.

    2006-12-01

    777 and 845 nm emissions from the 3p-3s multiplets of atomic oxygen are commonly observed at non-auroral latitudes in the terrestrial nightglow. By studying the relative strengths of these emissions we can learn something about the mechanisms that produce them and what they can teach us about the atmosphere. Recently [1] we have used intensity-calibrated sky spectra from the Keck telescopes to investigate the relative strengths of a wide range of O-atom Rydberg lines and have confirmed that electron-ion radiative recombination is a primary source of excitation for both the triplet and quintet systems. Following the intensity of the 777 and 845 nm lines during the night, we find that for most of the night the quintet 777 nm line is consistently stronger than the triplet 845 nm line, with a nearly constant intensity ratio I(777)/I(845) near 2.3, although both intensities fall rapidly as the night progresses. However, late in the night the 845 nm intensity levels off, while the 777 nm intensity continues to fall, and the I(777)/I(845) ratio plunges by a factor of 5-10. We interpret these observations as indicating that the O-atom quintet states are still being excited by the same mechanism as earlier in the night, i.e. radiative recombination, but some triplet states are also being excited by an additional mechanism. Such a mechanism has been proposed before [2-6] but not previously observed directly in the terrestrial nightglow. The oxygen triplet 3d-2p transition at 102.576 nm is in close coincidence with the solar hydrogen Lyman-β line at 102.572 nm. Radiative transport in the hydrogen geocorona will deliver Lyman-β intensity into the Earth's shadow and will produce triplet O(3d 3D) high in the atmosphere, even prior to direct solar illumination. The result is observable in a radiative cascade sequence 3d-3p(1129 nm) → 3p- 3s(845 nm) → 3s-2p(130 nm). A similar effect is observed in the H-α emission, which is also excited by Lyman-β absorption. This process

  11. A self-Q-switched all-fiber erbium laser at 1530 nm using an auxiliary 1570-nm erbium laser.

    PubMed

    Tsai, Tzong-Yow; Fang, Yen-Cheng

    2009-11-23

    We demonstrate a self-Q-switched, all-fiber, tunable, erbium laser at 1530 nm with high pulse repetition rates of 0.9-10 kHz. Through the use of an auxiliary 10-mW, 1570 nm laser that shortened the relaxation time of erbium, sequentially Q-switched pulses with pulse energies between 4 and 6 microJ and pulse widths of 40 ns were steadily achieved. A peak pulse power of 165 W was obtained.

  12. Imaging performance and challenges of 10nm and 7nm logic nodes with 0.33 NA EUV

    NASA Astrophysics Data System (ADS)

    van Setten, Eelco; Schiffelers, Guido; Psara, Eleni; Oorschot, Dorothe; Davydova, Natalia; Finders, Jo; Depre, Laurent; Farys, Vincent

    2014-10-01

    The NXE:3300B is ASML's third generation EUV system and has an NA of 0.33 and is positioned at a resolution of 22nm, which can be extended down to 18nm and below with off-axis illumination at full transmission. Multiple systems have been qualified and installed at customers. The NXE:3300B succeeds the NXE:3100 system (NA of 0.25), which has allowed customers to gain valuable EUV experience. It is expected that EUV will be adopted first for critical Logic layers at 10nm and 7nm nodes, such as Metal-1, to avoid the complexity of triple patterning schemes using ArF immersion. In this paper we will evaluate the imaging performance of (sub-)10nm node Logic M1 on the NXE:3300B EUV scanner. We will show the line-end performance of tip-to-tip and tip-to-space test features for various pitches and illumination settings and the performance enhancement obtained by means of a 1st round of OPC. We will also show the magnitude of local variations. The Logic M1 cell is evaluated at various critical features to identify hot spots. A 2nd round OPC model was calibrated of which we will show the model accuracy and ability to predict hot spots in the Logic M1 cell. The calibrated OPC model is used to predict the expected performance at 7nm node Logic using off-axis illumination at 16nm minimum half pitch. Initial results of L/S exposed on the NXE:3300B at 7nm node resolutions will be shown. An outlook is given to future 0.33 NA systems on the ASML roadmap with enhanced illuminator capabilities to further improve performance and process window.

  13. Detonation wave profiles measured in plastic bonded explosives using 1550 nm photon doppler velocimetry (PDV)

    SciTech Connect

    Gustavsen, Richard L; Bartram, Brian D; Sanchez, Nathaniel J

    2009-01-01

    We present detonation wave profiles measured in two TATB based explosives and two HMX based explosives. Profiles were measured at the interface of the explosive and a Lithium-Fluoride (LiF) window using 1550 nm Photon Doppler Velocimetry (PDV). Planar detonations were produced by impacting the explosive with a projectile launched in a gas-gun. The impact state was varied to produce varied distance to detonation, and therefore varied support of the Taylor wave following the Chapman-Jouget (CJ) or sonic state. Profiles from experiments with different support should be the same between the Von-Neumann (VN) spike and CJ state and different thereafter. Comparison of profiles with differing support, therefore, allows us to estimate reaction zone lengths. For the TATB based explosive, a reaction zone length of {approx} 3.9 mm, 500 ns was measured in EDC-35, and a reaction zone length of {approx} 6.3 mm, 800 ns was measured in PBX 9502 pre-cooled to -55 C. The respective VN spike state was 2.25 {+-} 0.05 km/s in EDC-35 and 2.4 {+-} 0.1 km/s in the cooled PBX 9502. We do not believe we have resolved either the VN spike state (> 2.6 km/s) nor the reaction zone length (<< 50 ns) in the HMX based explosives.

  14. Research of the Additional Losses Occurring in Optical Fiber at its Multiple Bends in the Range Waves 1310nm, 1550nm and 1625nm Long

    NASA Astrophysics Data System (ADS)

    Yurchenko, A. V.; Gorlov, N. I.; Alkina, A. D.; Mekhtiev, A. D.; Kovtun, A. A.

    2016-01-01

    Article is devoted to research of the additional losses occurring in the optical fiber at its multiple bends in the range waves of 1310 nanometers, 1550 nanometers and 1625 nanometers long. Article is directed on creation of the external factors methods which allow to estimate and eliminate negative influence. The automated way of calculation of losses at a bend is developed. Results of scientific researches are used by engineers of “Kazaktelekom” AS for practical definition of losses service conditions. For modeling the Wolfram|Alpha environment — the knowledge base and a set of computing algorithms was chosen. The greatest losses are noted on wavelength 1310nm and 1625nm. All dependences are nonlinear. Losses with each following excess are multiplicative.

  15. High-brightness 800nm fiber-coupled laser diodes

    NASA Astrophysics Data System (ADS)

    Berk, Yuri; Levy, Moshe; Rappaport, Noam; Tessler, Renana; Peleg, Ophir; Shamay, Moshe; Yanson, Dan; Klumel, Genadi; Dahan, Nir; Baskin, Ilya; Shkedi, Lior

    2014-03-01

    Fiber-coupled laser diodes have become essential sources for fiber laser pumping and direct energy applications. Single emitters offer reliable multi-watt output power from a 100 m lateral emission aperture. By their combination and fiber coupling, pump powers up to 100 W can be achieved from a low-NA fiber pigtail. Whilst in the 9xx nm spectral range the single emitter technology is very mature with <10W output per chip, at 800nm the reliable output power from a single emitter is limited to 4 W - 5 W. Consequently, commercially available fiber coupled modules only deliver 5W - 15W at around 800nm, almost an order of magnitude down from the 9xx range pumps. To bridge this gap, we report our advancement in the brightness and reliability of 800nm single emitters. By optimizing the wafer structure, laser cavity and facet passivation process we have demonstrated QCW device operation up to 19W limited by catastrophic optical damage to the 100 μm aperture. In CW operation, the devices reach 14 W output followed by a reversible thermal rollover and a complete device shutdown at high currents, with the performance fully rebounded after cooling. We also report the beam properties of our 800nm single emitters and provide a comparative analysis with the 9xx nm single emitter family. Pump modules integrating several of these emitters with a 105 μm / 0.15 NA delivery fiber reach 35W in CW at 808 nm. We discuss the key opto-mechanical parameters that will enable further brightness scaling of multi-emitter pump modules.

  16. Analysis of Cervical Supernatant Samples Luminescence Using 355 nm Laser

    NASA Astrophysics Data System (ADS)

    Vaitkuviene, A.; Gegzna, V.; Kurtinaitiene, R.; Stanikunas, R.; Rimiene, J.; Vaitkus, J.

    2010-05-01

    The biomarker discovery for accurate detection and diagnosis of cervical carcinoma and its malignant precursors represents one of the current challenges in clinical medicine. Laser induced autofluorescence spectra in cervical smear content were fitted to predict the cervical epithelium diagnosis as a lab off "optical biopsy" method. Liquid PAP supernatant sediment dried on Quartz plate spectroscopy was performed by 355 nm Nd YAG microlaser STA-1 (Standa, Ltd). For comparison a liquid supernatant spectroscopy was formed by laboratory "Perkin Elmer LS 50B spetrometer at 290, 300, 310 nm excitations. Analysis of spectrum was performed by approximation using the multi-peaks program with Lorentz functions for the liquid samples and with Gaussian functions for the dry samples. Ratio of spectral components area to the area under whole experimental curve (SPP) was calculated. The spectral components were compared by averages of SPP using Mann-Whitney U-test in histology groups. Results. Differentiation of Normal and HSIL/CIN2+ cases in whole supernatant could be performed by stationary laboratory lamp spectroscopy at excitation 290 nm and emission >379 nm with accuracy AUC 0,69, Sens 0,72, Spec 0,65. Differentiation Normal versus HSIL/CIN2+ groups in dried enriched supernatant could be performed by 355 nm microlaser excitation at emission 405-424 nm with accuracy (AUC 0,96, Sens 0,91, Spec 1.00). Diagnostic algorithm could be created for all histology groups differentiation under 355 nm excitation. Microlaser induced "optical biopsy "looks promising method for cervical screening at the point of care.

  17. Magnetoelastically induced magnetic anisotropy transition in [CoO5nm/CoPt7nm]5 multilayer films

    NASA Astrophysics Data System (ADS)

    Guo, Lei; Harumoto, Takashi; Sannomiya, Takumi; Muraishi, Shinji; Nakamura, Yoshio; Shi, Ji

    2016-06-01

    The magnetic anisotropy transition of [CoO5nm/CoPt7nm]5 multilayer film with respect to post-annealing has been studied systematically. It undergoes a smooth transition from longitudinal magnetic anisotropy (LMA) to perpendicular magnetic anisotropy (PMA) upon annealing and returns backward to LMA at high temperature of 550 °C. The strongest PMA of [CoO5nm/CoPt7nm]5 is achieved after post-annealing at 300 °C and the tolerable post-annealing temperature with strong PMA is up to 400 °C, which indicates this multilayer film could be a potential candidate for the PMA application at middle-high-temperature-region between 300 °C and 400 °C. The mechanism responsible for the transition of magnetic anisotropy has been investigated by analyzing CoO/CoPt interface and CoPt layer internal stress. It is found the effective PMA energy is proportional to the in-plane tensile stress of CoPt layer but is inversely proportional to the roughness of CoO/CoPt interface. Finally, by means of low temperature experiment we demonstrate the magnetic anisotropy transition observed in [CoO5nm/CoPt7nm]5 multilayer film is mainly attributed to the change of CoPt layer in-plane tensile stress.

  18. Optical coherence tomography based imaging of dental demineralisation and cavity restoration in 840 nm and 1310 nm wavelength regions

    NASA Astrophysics Data System (ADS)

    Damodaran, Vani; Rao, Suresh Ranga; Vasa, Nilesh J.

    2016-08-01

    In this paper, a study of in-house built optical coherence tomography (OCT) system with a wavelength of 840 nm for imaging of dental caries, progress in demineralisation and cavity restoration is presented. The caries when imaged with the 840 nm OCT system showed minute demineralisation in the order of 5 μm. The OCT system was also proposed to study the growth of lesion and this was demonstrated by artificially inducing caries with a demineralisation solution of pH 4.8. The progress of carious lesion to a depth of about 50-60 μm after 60 hours of demineralisation was clearly observed with the 840 nm OCT system. The tooth samples were subjected to accelerated demineralisation condition at pH of approximately 2.3 to study the adverse effects and the onset of cavity formation was clearly observed. The restoration of cavity was also studied by employing different restorative materials (filled and unfilled). In the case of restoration without filler material (unfilled), the restoration boundaries were clearly observed. Overall, results were comparable with that of the widely used 1310 nm OCT system. In the case of restoration with filler material, the 1310 nm OCT imaging displayed better imaging capacity due to lower scattering than 840 nm imaging.

  19. Fabricating nanopores with diameters of sub-1 nm to 3 nm using multilevel pulse-voltage injection.

    PubMed

    Yanagi, Itaru; Akahori, Rena; Hatano, Toshiyuki; Takeda, Ken-ichi

    2014-05-21

    To date, solid-state nanopores have been fabricated primarily through a focused-electronic beam via TEM. For mass production, however, a TEM beam is not suitable and an alternative fabrication method is required. Recently, a simple method for fabricating solid-state nanopores was reported by Kwok, H. et al. and used to fabricate a nanopore (down to 2 nm in size) in a membrane via dielectric breakdown. In the present study, to fabricate smaller nanopores stably--specifically with a diameter of 1 to 2 nm (which is an essential size for identifying each nucleotide)--via dielectric breakdown, a technique called "multilevel pulse-voltage injection" (MPVI) is proposed and evaluated. MPVI can generate nanopores with diameters of sub-1 nm in a 10-nm-thick Si3N4 membrane with a probability of 90%. The generated nanopores can be widened to the desired size (as high as 3 nm in diameter) with sub-nanometre precision, and the mean effective thickness of the fabricated nanopores was 3.7 nm.

  20. Observation of Quiet Limb in He I 1083.0 nm, H Paschen alpha1281.8 nm and H Brackett gamma 2166.1 nm lines

    NASA Astrophysics Data System (ADS)

    Prasad Choudhary, Debi

    2016-05-01

    In this paper, we shall present the results of an observational study of the quiet solar limb in the near infrared lines using the New IR Array Camera (NAC) and the vertical spectrograph at the focal plane of McMath-Pierce telescope. The NAC, at the exit port of the spectrograph, was used to record the limb spectrum in HeI 1083.0 nm, Hydrogen Paschen 1281.8 nm and Brackett 2165.5 nm wavelength regions. The NAC is a 1024x1024 InSb Alladin III Detector operating over 1-5 micron range with high density sampling at 0.018 arc second/pixel. The all-reflective optical train minimizes number of surfaces and eliminates ghosts leading to low scatter, ghost-free optics. The close-cycle cryogenic provides a stable cooling environment over six hour period with an accuracy of 0.01K leading to low dark current. The low read out noise combined with low scattered light and dark current makes NAC an ideal detector for making high quality infrared spectral observations of solar limb. The limb spectrums were obtained by placing the spectrograph slit perpendicular to the limb at an interval of 10 degrees around the solar disk. We shall report the intensity profile, line-of-sight velocity and line width distribution around the sun derived from the spectra along the slit.

  1. The enhancement of 21.2%-power conversion efficiency in polymer photovoltaic cells by using mixed Au nanoparticles with a wide absorption spectrum of 400 nm-1000 nm

    NASA Astrophysics Data System (ADS)

    Hao, Jing-Yu; Xu, Ying; Zhang, Yu-Pei; Chen, Shu-Fen; Li, Xing-Ao; Wang, Lian-Hui; Huang, Wei

    2015-04-01

    Au nanoparticles (NPs) mixed with a majority of bone-like, rod, and cube shapes and a minority of irregular spheres, which can generate a wide absorption spectrum of 400 nm-1000 nm and three localized surface plasmon resonance peaks, respectively, at 525, 575, and 775 nm, are introduced into the hole extraction layer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) to improve optical-to-electrical conversion performances in polymer photovoltaic cells. With the doping concentration of Au NPs optimized, the cell performance is significantly improved: the short-circuit current density and power conversion efficiency of the poly(3-hexylthiophene): [6,6]-phenyl-C60-butyric acid methyl ester cell are increased by 20.54% and 21.2%, reaching 11.15 mA·cm-2 and 4.23%. The variations of optical, electrical, and morphology with the incorporation of Au NPs in the cells are analyzed in detail, and our results demonstrate that the cell performance improvement can be attributed to a synergistic reaction, including: 1) both the localized surface plasmon resonance- and scattering-induced absorption enhancement of the active layer, 2) Au doping-induced hole transport/extraction ability enhancement, and 3) large interface roughness-induced efficient exciton dissociation and hole collection. Project supported by the National Basic Research Program of China (Grant Nos. 2015CB932202 and 2012CB933301), the National Natural Science Foundation of China (Grant Nos. 61274065, 51173081, 61136003, BZ2010043, 51372119, and 51172110), the Science Fund from the Ministry of Education of China (Grant No. IRT1148), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20113223110005), the Priority Academic Program Development of Jiangsu Provincial Higher Education Institutions (Grant No. YX03001), and the National Synergistic Innovation Center for Advanced Materials and the Synergetic Innovation Center for Organic Electronics and

  2. Extensive angiokeratoma circumscriptum - successful treatment with 595-nm variable-pulse pulsed dye laser and 755-nm long-pulse pulsed alexandrite laser.

    PubMed

    Baumgartner, Ján; Šimaljaková, Mária; Babál, Pavel

    2016-06-01

    Angiokeratomas are rare vascular mucocutaneous lesions characterized by small-vessel ectasias in the upper dermis with reactive epidermal changes. Angiokeratoma circumscriptum (AC) is the rarest among the five types in the current classification of angiokeratoma. We present a case of an extensive AC in 19-year-old women with Fitzpatrick skin type I of the left lower extremity, characterized by a significant morphological heterogeneity of the lesions, intermittent bleeding, and negative psychological impact. Histopathological examination after deep biopsy was consistent with that of angiokeratoma. The association with metabolic diseases (Fabry disease) was excluded by ophthalmological, biochemical, and genetic examinations. Nuclear magnetic resonance imaging has not detected deep vascular hyperplasia pathognomic for verrucous hemangioma. The combined treatment with 595-nm variable-pulse pulsed dye laser (VPPDL) and 755-nm long-pulse pulsed alexandrite laser (LPPAL) with dynamic cooling device led to significant removal of the pathological vascular tissue of AC. Only a slight degree of secondary reactions (dyspigmentations and texture changes) occurred. No recurrence was observed after postoperative interval of 9 months. We recommend VPPDL and LPPAL for the treatment of extensive AC.

  3. Skin reactions to sunscreens.

    PubMed

    Nixon, R L; Frowen, K E; Lewis, A E

    1997-06-01

    Sunscreen reactions are said not to be uncommon. A population referred to a patch testing clinic was evaluated for reactions to sunscreen by questionnaire initially and then, if relevant, by patch testing to sunscreen products and their components. Irritant reactions were more common than allergic contact dermatitis. Allergic reactions to sunscreens were less common than to non-sunscreen chemicals present in sunscreen products.

  4. The Glyoxal Clock Reaction

    ERIC Educational Resources Information Center

    Ealy, Julie B.; Negron, Alexandra Rodriguez; Stephens, Jessica; Stauffer, Rebecca; Furrow, Stanley D.

    2007-01-01

    Research on the glyoxal clock reaction has led to adaptation of the clock reaction to a general chemistry experiment. This particular reaction is just one of many that used formaldehyde in the past. The kinetics of the glyoxal clock makes the reaction suitable as a general chemistry lab using a Calculator Based Laboratory (CBL) or a LabPro. The…

  5. Quantum yield for carbon monoxide production in the 248 nm photodissociation of carbonyl sulfide (OCS)

    SciTech Connect

    Zhao, Z.; Stickel, R.E.; Wine, P.H.

    1995-03-01

    Tunable diode laser absorption spectroscopy has been coupled with excimer laser flash photolysis to measure the quantum yield for CO production from 248 nm photodissociation of carbonyl sulfide (OCS) relative to the well known quantum yield for CO production from 248 nm photolysis of phosgene (Cl{sub 2}CO). The temporal resolution of the experiments was sufficient to distinguish CO formed directly by photodissociation from that formed by subsequent S({sup 3}P{sub j}) reaction with OCS. Under the experimental conditions employed, CO formation via the fast S({sup 1}D{sub 2})+OCS reaction was minimal. Measurements at 297K and total pressures from 4 to 100 Torr N{sub 2}+N{sub 2}O show the CO yield to be greater than 0.95 and most likely unity. This result suggests that the contribution of OCS as a precursor to the lower stratospheric sulfate aerosol layer is somewhat larger than previously thought. 25 refs., 1 fig., 2 tabs.

  6. Kinetics and mechanism investigation on the destruction of oxytetracycline by UV-254nm activation of persulfate.

    PubMed

    Liu, Yiqing; He, Xuexiang; Fu, Yongsheng; Dionysiou, Dionysios D

    2016-03-15

    Oxytetracycline (OTC), an important broad-spectrum antibiotic, has been detected extensively in various environmental systems, which may have a detrimental impact on ecosystem and human health through the development of drug resistant bacteria and pathogens. In this study, the degradation of OTC was evaluated by UV-254nm activated persulfate (PS). The observed UV fluence based pseudo first-order rate constant (kobs) was found to be the highest at near neutral pH conditions (pH 5.5-8.5). Presence of various natural water constituents had different effects on OTC degradation, with a significant enhancement in the presence of bicarbonate or Cu(2+). Limited elimination of total organic carbon (TOC) and PS was observed during the mineralization of OTC. Transformation byproducts in the presence and absence of hydroxyl radical scavenging agent tert-butanol (t-BuOH) were identified using ultra-high definition accurate-mass quadrupole time-of-flight liquid chromatography/mass spectrometer (LC-QTOF/MS). Potential OTC degradation mechanism was subsequently proposed revealing four different reaction pathways by SO4(-) reaction including hydroxylation (+16Da), demethylation (-14Da), decarbonylation (-28Da) and dehydration (-18Da). This study suggests that UV-254nm/PS is a promising treatment technology for the control of water pollution caused by emerging contaminants such as OTC.

  7. Taking the X Architecture to the 65-nm technology node

    NASA Astrophysics Data System (ADS)

    Sarma, Robin C.; Smayling, Michael C.; Arora, Narain; Nagata, Toshiyuki; Duane, Michael P.; Shah, Santosh; Keston, Harris J.; Oemardani, Shiany

    2004-05-01

    The X Architecture is a new way of orienting the interconnect on an integrated circuit using diagonal pathways, as well as the traditional right-angle, or Manhattan, configuration. By enabling designs with significantly less wire and fewer vias, the X Architecture can provide substantial improvements in chip performance, power consumption and cost. Members of the X Initiative semiconductor supply chain consortium have demonstrated the production worthiness of the X Architecture at the 130-nm and 90-nm process technology nodes. This paper presents an assessment of the manufacturing readiness of the X Architecture for the 65-nm technology node. The extent to which current production capabilities in mask writing, lithography, wafer processing, inspection and metrology can be used is discussed using the results from a 65-nm test chip. The project was a collaborative effort amongst a number of companies in the IC fabrication supply chain. Applied Materials fabricated the 65-nm X Architecture test chip at its Maydan Technology Center and leveraged the technology of other X Initiative members. Cadence Design Systems provided the test structure design and chip validation tools, Dai Nippon Printing produced the masks and Canon"s imaging system was employed for the photolithography.

  8. Imaging CIN(3) photodissociation from 234 to 280 nm.

    PubMed

    Samartzis, Peter C; Hansen, Nils; Wodtke, Alec M

    2006-07-07

    We report Cl((2)P(3/2)) and Cl*((2)P(1/2)) fragment images following ClN(3) photolysis in the 234-280 nm region measured by velocity map imaging. Kinetic energy distributions change shape with photolysis wavelength from bimodal at 234 and 240 nm to single peak at 266 and 280 nm. Where two peaks exist, their ratio is significantly different for Cl and Cl* fragments. The single peak of 266 and 280 nm and the faster peak at 234 and 240 nm are assigned to a Cl + linear-N(3) dissociation channel, in agreement with previous work. The slow peak in the bimodal distributions is assigned to the formation of a high energy form (HEF) of N(3). Candidates for the identity of HEF-N(3) are discussed. Combining our data with photofragmentation translational spectroscopy results, we determined the threshold for the appearance of HEF-N(3) at 4.83 +/- 0.17 eV photolysis energy. This threshold behavior is similar to recently reported results on the wavelength dependence of HN(3) photolysis, where the threshold was associated with a ring closed isomer of HN(3) on the S(1) potential energy surface. We also note that the HEF-N(3) formation threshold observed for ClN(3) occurs where the energy available to the products equals the isomerization barrier from linear to cyclic-N(3).

  9. Process liability evaluation for beyond 22nm node using EUVL

    NASA Astrophysics Data System (ADS)

    Tawarayama, Kazuo; Aoyama, Hajime; Matsunaga, Kentaro; Arisawa, Yukiyasu; Uno, Taiga; Magoshi, Shunko; Kyoh, Suigen; Nakajima, Yumi; Inanami, Ryoichi; Tanaka, Satoshi; Kobiki, Ayumi; Kikuchi, Yukiko; Kawamura, Daisuke; Takai, Kosuke; Murano, Koji; Hayashi, Yumi; Mori, Ichiro

    2010-04-01

    Extreme ultraviolet lithography (EUVL) is the most promising candidate for the manufacture of devices with a half pitch of 32 nm and beyond. We are now evaluating the process liability of EUVL in view of the current status of lithography technology development. In a previous study, we demonstrated the feasibility of manufacturing 32-nm-node devices by means of a wafer process that employed the EUV1, a full-field step-and-scan exposure tool. To evaluate yield, a test pattern was drawn on a multilayer resist and exposed. After development, the pattern was replicated in SiO2 film by etching, and metal wires were formed by a damascene process. Resolution enhancement is needed to advance to the 22- nm node and beyond, and a practical solution is off-axis illumination (OAI). This paper presents the results of a study on yield improvement that used a 32-nm-node test chip, and also clarifies a critical issue in the use of EUVL in a wafer process for device manufacture at the 22-nm node and beyond.

  10. Absorption spectrum of DNA for wavelengths greater than 300 nm

    SciTech Connect

    Sutherland, J.C.; Griffin, K.P.

    1981-06-01

    Although DNA absorption at wavelengths greater than 300 nm is much weaker than that at shorter wavelengths, this absorption seems to be responsible for much of the biological damage caused by solar radiation of wavelengths less than 320 nm. Accurate measurement of the absorption spectrum of DNA above 300 nm is complicated by turbidity characteristic of concentrated solutions of DNA. We have measured the absorption spectra of DNA from calf thymus, Clostridium perfringens, Escherichia coli, Micrococcus luteus, salmon testis, and human placenta using procedures which separate optical density due to true absorption from that due to turbidity. Above 300 nm, the relative absorption of DNA increases as a function of guanine-cytosine content, presumably because the absorption of guanine is much greater than the absorption of adenine at these wavelengths. This result suggests that the photophysical processes which follow absorption of a long-wavelength photon may, on the average, differ from those induced by shorter-wavelength photons. It may also explain the lower quantum yield for the killing of cells by wavelengths above 300 nm compared to that by shorter wavelengths.

  11. A cesium bromide photocathode excited by 405 nm radiation

    NASA Astrophysics Data System (ADS)

    Maldonado, J. R.; Cheng, Y. T.; Pianetta, P.; Pease, Fabian W.; Hesselink, L.

    2014-07-01

    In several applications, such as electron beam lithography and X-ray differential phase contrast imaging, there is a need for a free electron source with a current density at least 10 A/cm2 yet can be shaped with a resolution down to 20 nm and pulsed. Additional requirements are that the source must operate in a practical demountable vacuum (>1e-9 Torr) and be reasonably compact. In prior work, a photocathode comprising a film of CsBr on metal film on a sapphire substrate met the requirements except it was bulky because it required a beam (>10 W/cm2) of 257 nm radiation. Here, we describe an approach using a 405 nm laser which is far less bulky. The 405 nm laser, however, is not energetic enough to create color centers in CsBr films. The key to our approach is to bombard the CsBr film with a flood beam of about 1 keV electrons prior to operation. Photoelectron efficiencies in the range of 100-1000 nA/mW were demonstrated with lifetimes exceeding 50 h between electron bombardments. We suspect that the electron bombardment creates intraband color centers whence electrons can be excited by the 405 nm photons into the conduction band and thence into the vacuum.

  12. Facile Synthesis of Sub-20 nm Silver Nanowires through a Bromide-Mediated Polyol Method.

    PubMed

    da Silva, Robson Rosa; Yang, Miaoxin; Choi, Sang-Il; Chi, Miaofang; Luo, Ming; Zhang, Chao; Li, Zhi-Yuan; Camargo, Pedro H C; Ribeiro, Sidney José Lima; Xia, Younan

    2016-08-23

    Essentially all of the Ag nanowires reported in the literature have sizes larger than 30 nm in diameter. In this article, we report a simple and robust approach to the synthesis of Ag nanowires with diameters below 20 nm and aspect ratios over 1000 using a one-pot polyol method. The Ag nanowires took a penta-twinned structure, and they could be obtained rapidly (<35 min) and in high morphology purity (>85% of the as-obtained solid product) under atmospheric pressure. The key to the success of this synthesis is to restrain the nanowires from lateral growth by employing both Br(-) ions and poly(vinylpyrrolidone) with a high molecular weight of 1 300 000 g/mol to cap the {100} side faces, together with the use of a syringe pump to slowly introduce AgNO3 into the reaction solution. By optimizing the ratios between the capping agents and AgNO3, we were able to slow down the reduction kinetics and effectively direct the Ag nanowires to grow along the longitudinal direction only. The nanowires showed great mechanical flexibility and could be bent with acute angles without breaking. Because of their small diameters, the transverse localized surface plasmon resonance peak of the Ag nanowires could be pushed down to the ultraviolet region, below 400 nm, making them ideal conductive elements for the fabrication of touch screens, solar cells, and smart windows.

  13. Synthesis and Characterization of L-Lysine Conjugated Silver Nanoparticles Smaller Than 10 nM

    PubMed Central

    Bonor, Jeremy; Reddy, Vandhana; Akkiraju, Hemanth; Dhurjati, Prasad; Nohe, Anja

    2015-01-01

    A rapid and convenient batch method for synthesizing lysine-conjugated silver nanoparticles of approximately 5 nm of size was developed. Nanoparticles of size less than 100 nm exhibit significant medical potential. L-Lysine demonstrates potential for therapeutic applications and silver nanoparticles are an optimal choice for drug delivery because of its intrinsic anti-platelet, anti-bacterial and anti-inflammatory capabilities. Current synthesis protocols for Lysine-capped particles under 10 nm are time consuming and tedious and allow only for the sythesis of small quantities of particles. The synthesis of Lysin-capped silver nanoparticles was based on the reaction in which AgNO3 was reduced by excess NaBH4. L-Lysine, a known essential amino acid, served as the capping agent to minimize initial aggregation. The particles were then separated by size chromatography. Capping occurred through the amide bond on L-Lysine as determined by FT-IR. The conjugation of the particle to the amide bond is important, since this leaves the amino group of Lysine open to further modifications. The particles were further characterized in regards to their shape, size and stability. Finally we demonstrated that the synthesized particles exhibit limited to no toxicity in cells, using HEK 293 cell line as a model system. Our sythesis protocol can be successfully used for scale-up and synthesis of high quantities of nanoparticles. PMID:26478827

  14. Effects of amines on formation of sub-3 nm particles and their subsequent growth

    SciTech Connect

    Yu H.; McGraw R.; Lee S.-H.

    2012-01-28

    Field observations and quantum chemical calculations suggest that amines can be important for formation of nanometer size particles. Amines and ammonia often have common atmospheric emission sources and the similar chemical and physical properties. While the effects of ammonia on aerosol nucleation have been previously investigated, laboratory studies of homogeneous nucleation involving amines are lacking. We have made kinetics studies of multicomponent nucleation (MCN) with sulfuric acid, water, ammonia and amines under conditions relevant to the atmosphere. Low concentrations of aerosol precursors were measured with chemical ionization mass spectrometers (CIMS) to provide constrained precursor concentrations needed for nucleation. Particle sizes larger than {approx}2 nm were measured with a nano-differential mobility analyzer (nano-DMA), and number concentrations of particles larger than {approx}1 nm were measured with a particle size magnifier (PSM). Our observations provide the laboratory evidence that amines indeed can participate in aerosol nucleation and growth at the molecular cluster level. The enhancement of particle number concentrations due to several atmospherically relevant amine compounds and ammonia were related to the basicity of these compounds, indicating that acid-base reactions may contribute to the formation of sub-3 nm particles.

  15. Cavity-enhanced measurements of hydrogen peroxide absorption cross sections from 353 to 410 nm.

    PubMed

    Kahan, Tara F; Washenfelder, Rebecca A; Vaida, Veronica; Brown, Steven S

    2012-06-21

    We report near-ultraviolet and visible absorption cross sections of hydrogen peroxide (H(2)O(2)) using incoherent broad-band cavity-enhanced absorption spectroscopy (IBBCEAS), a recently developed, high-sensitivity technique. The measurements reported here span the range of 353-410 nm and extend published electronic absorption cross sections by 60 nm to absorption cross sections below 1 × 10(-23) cm(2) molecule(-1). We have calculated photolysis rate constants for H(2)O(2) in the lower troposphere at a range of solar zenith angles by combining the new measurements with previously reported data at wavelengths shorter than 350 nm. We predict that photolysis at wavelengths longer than those included in the current JPL recommendation may account for up to 28% of the total hydroxyl radical (OH) production from H(2)O(2) photolysis under some conditions. Loss of H(2)O(2) via photolysis may be of the same order of magnitude as reaction with OH and dry deposition in the lower atmosphere; these processes have very different impacts on HO(x) loss and regeneration.

  16. Reaction Selectivity in Heterogeneous Catalysis

    SciTech Connect

    Somorjai, Gabor A.; Kliewer, Christopher J.

    2009-02-02

    The understanding of selectivity in heterogeneous catalysis is of paramount importance to our society today. In this review we outline the current state of the art in research on selectivity in heterogeneous catalysis. Current in-situ surface science techniques have revealed several important features of catalytic selectivity. Sum frequency generation vibrational spectroscopy has shown us the importance of understanding the reaction intermediates and mechanism of a heterogeneous reaction, and can readily yield information as to the effect of temperature, pressure, catalyst geometry, surface promoters, and catalyst composition on the reaction mechanism. DFT calculations are quickly approaching the ability to assist in the interpretation of observed surface spectra, thereby making surface spectroscopy an even more powerful tool. HP-STM has revealed three vitally important parameters in heterogeneous selectivity: adsorbate mobility, catalyst mobility, and selective site-blocking. The development of size controlled nanoparticles from 0.8 to 10 nm, of controlled shape, and of controlled bimetallic composition has revealed several important variables for catalytic selectivity. Lastly, DFT calculations may be paving the way to guiding the composition choice for multi-metallic heterogeneous catalysis for the intelligent design of catalysts incorporating the many factors of selectivity we have learned.

  17. High Power 938nm Cladding Pumped Fiber Laser

    SciTech Connect

    Dawson, J; Beach, R; Brobshoff, A; Liao, Z; Payne, S; Pennington, D; Taylor, L; Hackenberg, W; Bonaccini, D

    2002-12-26

    We have developed a Nd:doped cladding pumped fiber amplifier, which operates at 938nm with greater than 2W of output power. The core co-dopants were specifically chosen to enhance emission at 938nm. The fiber was liquid nitrogen cooled in order to achieve four-level laser operation on a laser transition that is normally three level at room temperature, thus permitting efficient cladding pumping of the amplifier. Wavelength selective attenuation was induced by bending the fiber around a mandrel, which permitted near complete suppression of amplified spontaneous emission at 1088nm. We are presently seeking to scale the output of this laser to 10W. We will discuss the fiber and laser design issues involved in scaling the laser to the 10W power level and present our most recent results.

  18. Incoherent magnetization reversal in 30-nm Ni particles

    NASA Astrophysics Data System (ADS)

    Ross, C. A.; Chantrell, R.; Hwang, M.; Farhoud, M.; Savas, T. A.; Hao, Y.; Smith, Henry I.; Ross, F. M.; Redjdal, M.; Humphrey, F. B.

    2000-12-01

    The magnetic properties of a 100-nm-period large-area array of regular, 30-nm polycrystalline nickel particles have been studied. The particles are found to reverse incoherently, and their hysteresis behavior has been compared with a computational model over a range of temperatures. Excellent agreement with the model is obtained, indicating that switching of the particles is dominated by the reversal of approximately 10-nm-diameter volumes within each particle. These switching volumes are identified with the columnar grains in the polycrystalline nickel, showing that the microstructure determines the magnetic behavior of the particles. This explains the anisotropy distribution and the onset of superparamagnetism in the sample. Incoherent reversal occurs even though the particles are only 1.5 times the exchange length in nickel, a size at which nearly uniform rotation is expected to occur if the particles were homogeneous.

  19. Interaction between Nm23 and the tumor suppressor VHL.

    PubMed

    Lin, Chih-Hung; Dammai, Vincent; Adryan, Boris; Hsu, Tien

    2015-02-01

    Among the anti-tumor genes (tumor suppressors and metastasis suppressors), the von-Hippel Lindau gene and the Nm23 family of genes are among the more intriguing ones. Both are small (long and short forms of VHL are 30 and 19 kD, respectively, and Nm23 is ~17 kD), and both possess diverse molecular and cellular functions. Despite extensive studies, the entire spectra of functions and the molecular function-phenotype correlation of these two proteins have not been completely elucidated. In this report, we present data showing these two proteins interact physically. We also summarize and confirm the previous studies that demonstrated the endocytic function of these two genes and further show that the endocytic function of VHL is mediated through the activity of Nm23. These functional and molecular interactions are evolutionarily conserved from Drosophila to human.

  20. High power narrowband 589 nm frequency doubled fibre laser source.

    PubMed

    Taylor, Luke; Feng, Yan; Calia, Domenico Bonaccini

    2009-08-17

    We demonstrate high-power high-efficiency cavity-enhanced second harmonic generation of an in-house built ultra-high spectral density (SBS-suppressed) 1178 nm narrowband Raman fibre amplifier. Up to 14.5 W 589 nm CW emission is achieved with linewidth Delta nu(589) < 7 MHz in a diffraction-limited beam, with peak external conversion efficiency of 86%. The inherently high spectral and spatial qualities of the 589 nm source are particularly suited to both spectroscopic and Laser Guide Star applications, given the seed laser can be easily frequency-locked to the Na D(2a) emission line. Further, we expect the technology to be extendable, at similar or higher powers, to wavelengths limited only by the seed-pump-pair availability.

  1. Ion Imaging Studies of CH_2I_2 Photodissociation at 248 NM

    NASA Astrophysics Data System (ADS)

    Lehman, Julia H.; Li, Hongwei; Lester, Marsha I.

    2013-06-01

    CH_2I_2 plays an important role in atmospheric chemistry as a significant natural source of organohalide compounds. The photodissociation dynamics of CH_2I_2 in the ultraviolet range of 277-305 nm via the two lowest B_1 excited states has been well studied using one-color velocity map ion imaging (VMI) and photofragment translational spectroscopy. In this two-color experimental study, CH_2I_2 is photodissociated by 248 nm via the B_2 or A_1 excited states to give rise to CH_2I and I (^2P_3_/_2) or I^* (^2P_1_/_2). The iodine atoms are then state selectively ionized using a (2+1) resonance-enhanced multiphoton ionization process near 310 nm and detected by VMI. Preliminary results show about 85% of the available energy is being funneled into the internal energy of the CH_2I fragment, consistent with prior infrared emission results of Baughcum and Leone. The anisotropy parameter derived from the image indicates this is a fast dissociation process and reflects the character of the electronic transition. The internal energy distribution of the CH_2I fragment is of particular interest because of its subsequent reaction with O_2 in a near thermo-neutral reaction to produce the smallest Criegee intermediate, CH_2OO. We anticipate that the internal energy contained in CH_2I will likely be carried into CH_2OO. S. L. Baughcum and S. R. Leone, J. Chem. Phys. 72, 6531 (1980).

  2. Photochemical cycloaddition reactions of cyanoacetylene and dicyanoacetylene

    NASA Technical Reports Server (NTRS)

    Ferris, J. P.; Guillemin, J. C.

    1990-01-01

    Photolysis of cyanoacetylene with 185- or 206-nm light yields 1,3,5-tricyanobenzene while 254-nm radiation yields a mixture of tetracyanocyclooctatetraenes, 1,2,4- and 1,3,5-tricyanobenzene. A polymer of cyanoacetylene is the major photoproduct. 1,3,5-Tricarbomethoxybenzene was the only photoproduct identified from the irradiation of methyl propiolate at 254 nm. Mono-, di-, and tricyanobenzenes are formed by irradiation of mixtures of acetylene and cyanoacetylene at 185, 206, and 254 nm along with trace amounts of cyclooctatetraenes. No photoadducts were detected on photolysis of mixtures of cyanoacetylene and CO or HCN. The tetracyanocyclooctatetraene structures were established by UV, MS, and NMR analyses. The 1H NMR of the product mixture exhibited a singlet at delta 7.028 consistent with either 1 or 2 and two singlets at delta 6.85 and 6.91 assigned to 3. Photolysis of mixtures of dicyanoacetylene and acetylene with either 185- or 206-nm light yielded 1,2-dicyanobenzene and (E,Z)-1-buten-3-yne-1,4-dicarbonitrile. These products were also obtained using 254-nm light along with a mixture of tetracyanocyclooctatetraenes. The same three singlets were observed in this product mixture as were observed in the tetracyanocyclooctatetraenes obtained from cyanoacetylene. From this observation it was concluded that the delta 7.02 signal is due to 2 and not 1. The photolysis of cyanoacetylene and dicyanoacetylene in the presence of ethylene with 185-nm light yields 1-cyanocylobutene and 1,2-dicyanocyclobutene, respectively. 2-Cyanobutadiene and 2,3-dicyanobutadiene are the photoproducts with 254-nm light. Reaction pathways are proposed to explain these findings.

  3. 32 nm imprint masks using variable shape beam pattern generators

    NASA Astrophysics Data System (ADS)

    Selinidis, Kosta; Thompson, Ecron; Schmid, Gerard; Stacey, Nick; Perez, Joseph; Maltabes, John; Resnick, Douglas J.; Yeo, Jeongho; Kim, Hoyeon; Eynon, Ben

    2008-05-01

    Imprint lithography has been included on the ITRS Lithography Roadmap at the 32, 22 and 16 nm nodes. Step and Flash Imprint Lithography (S-FIL ®) is a unique method that has been designed from the beginning to enable precise overlay for creating multilevel devices. A photocurable low viscosity monomer is dispensed dropwise to meet the pattern density requirements of the device, thus enabling imprint patterning with a uniform residual layer across a field and across entire wafers. Further, S-FIL provides sub-100 nm feature resolution without the significant expense of multi-element, high quality projection optics or advanced illumination sources. However, since the technology is 1X, it is critical to address the infrastructure associated with the fabrication of templates. For sub-32 nm device manufacturing, one of the major technical challenges remains the fabrication of full-field 1x templates with commercially viable write times. Recent progress in the writing of sub-40 nm patterns using commercial variable shape e-beam tools and non-chemically amplified resists has demonstrated a very promising route to realizing these objectives, and in doing so, has considerably strengthened imprint lithography as a competitive manufacturing technology for the sub 32nm node. Here we report the first imprinting results from sub-40 nm full-field patterns, using Samsung's current flash memory production device design. The fabrication of the template is discussed and the resulting critical dimension control and uniformity are discussed, along with image placement results. The imprinting results are described in terms of CD uniformity, etch results, and overlay.

  4. Full-field imprinting of sub-40 nm patterns

    NASA Astrophysics Data System (ADS)

    Yeo, Jeongho; Kim, Hoyeon; Eynon, Ben

    2008-03-01

    Imprint lithography has been included on the ITRS Lithography Roadmap at the 32, 22 and 16 nm nodes. Step and Flash Imprint Lithography (S-FIL (R)) is a unique patterning method that has been designed from the beginning to enable precise overlay to enable multilevel device fabrication. A photocurable low viscosity resist is dispensed dropwise to match the pattern density requirements of the device, thus enabling patterning with a uniform residual layer thickness across a field and across multiple wafers. Further, S-FIL provides sub-50 nm feature resolution without the significant expense of multi-element projection optics or advanced illumination sources. However, since the technology is 1X, it is critical to address the infrastructure associated with the fabrication of imprint masks (templates). For sub-32 nm device manufacturing, one of the major technical challenges remains the fabrication of full-field 1x imprint masks with commercially viable write times. Recent progress in the writing of sub-40 nm patterns using commercial variable shape e-beam tools and non-chemically amplified resists has demonstrated a very promising route to realizing these objectives, and in doing so, has considerably strengthened imprint lithography as a competitive manufacturing technology for the sub-32nm node. Here we report the first imprinting results from sub-40 nm full-field patterns, using Samsung's current flash memory production device design. The fabrication of the imprint mask and the resulting critical dimension control and uniformity are discussed, along with image placement results. The imprinting results are described in terms of CD uniformity, etch results, and overlay.

  5. Low-loss arrayed waveguide grating at 760 nm.

    PubMed

    Stanton, E J; Spott, A; Davenport, M L; Volet, N; Bowers, J E

    2016-04-15

    An arrayed waveguide grating (AWG) at 760 nm is demonstrated with an insertion loss smaller than 0.5 dB. Interface roughness and waveguide length errors contribute much more to scattering loss and phase errors at 760 nm than at longer wavelengths, thus requiring improved design and fabrication. This Letter details how this is achieved by minimizing interfacial scattering, grating side-order excitation, and phase errors in the AWG. With silicon nitride core and silicon dioxide clad waveguides on silicon, this AWG is compatible with heterogeneously integrated lasers for on-chip spectral beam combining.

  6. Cost-effective tunable 1310nm DWDM transmitter

    NASA Astrophysics Data System (ADS)

    Chorchos, Łukasz; Turkiewicz, Jarosław P.

    2015-09-01

    The growing demand for higher data rate transmissions in local and metropolitan area networks is main reason of developing effective and inexpensive transmission systems. In this paper, study about the possibility to realize 1310 nm tunable DWDM transmitter using commercially available low-cost DFB lasers is presented. Extensive DFB lasers characterization has been performed which led to establish relationships between laser current, operational temperature, emitted wavelength and power. An algorithm to find the laser settings for a desired wavelength grid has been proposed and tested. Generation of the 1310nm DWDM channels with frequency spacing between 120 and 240GHz has been demonstrated.

  7. 670 nm light mitigates oxygen-induced degeneration in C57BL/6J mouse retina

    PubMed Central

    2013-01-01

    Background Irradiation with light wavelengths from the far red (FR) to the near infrared (NIR) spectrum (600 nm -1000 nm) has been shown to have beneficial effects in several disease models. In this study, we aim to examine whether 670 nm red light pretreatment can provide protection against hyperoxia-induced damage in the C57BL/6J mouse retina. Adult mice (90–110 days) were pretreated with 9 J/cm2 of 670 nm light once daily for 5 consecutive days prior to being placed in hyperoxic environment (75% oxygen). Control groups were exposed to hyperoxia, but received no 670 nm light pretreatment. Retinas were collected after 0, 3, 7, 10 or 14 days of hyperoxia exposure (n = 12/group) and prepared either for histological analysis, or RNA extraction and quantitative polymerase chain reaction (qPCR). Photoreceptor damage and loss were quantified by counting photoreceptors undergoing cell death and measuring photoreceptor layer thickness. Localization of acrolein, and cytochrome c oxidase subunit Va (Cox Va) were identified through immunohistochemistry. Expression of heme oxygenase-1 (Hmox-1), complement component 3 (C3) and fibroblast growth factor 2 (Fgf-2) genes were quantified using qPCR. Results The hyperoxia-induced photoreceptor loss was accompanied by reduction of metabolic marker, Cox Va, and increased expression of oxidative stress indicator, acrolein and Hmox-1. Pretreatment with 670 nm red light reduced expression of markers of oxidative stress and C3, and slowed, but did not prevent, photoreceptor loss over the time course of hyperoxia exposure. Conclusion The damaging effects of hyperoxia on photoreceptors were ameliorated following pretreatment with 670 nm light in hyperoxic mouse retinas. These results suggest that pretreatment with 670 nm light may provide stability to photoreceptors in conditions of oxidative stress. PMID:24134095

  8. First results from simultaneous 527 nm and 351 nm probe beam interactions in a long scalelength plasma

    NASA Astrophysics Data System (ADS)

    Moody, J. D.; MacKinnon, A.; Glenzer, S. H.; Froula, D.; Gregori, G.; Berger, R. L.; Campbell, K.; Divol, L.; Dixit, S.; Suter, L. J.; Williams, E. A.; Bahr, R.; Seka, W.

    2002-11-01

    We investigate the stimulated Raman and Brillouin backscattered light from simultaneous 527 nm and 351 nm probe beams incident on a long scalelength ignition-like plasma. These experiments are important for both determining backscattering physics mechanisms and for evaluating laser power loss expected in planned ignition experiments. The plasma is formed using 18 kJ of 351 nm light from the Omega laser in a 1 ns pulse incident on a gas-filled balloon target. The two probe beams, which are delayed 0.5 ns relative to the plasma forming beams, are separated by 42^rc, have vacuum intensity of <= 7 × 10^14 W/cm^2 and may or may not intersect in the plasma. Self-Thomson scattered light from the 527 nm beam is used to determine the plasma temperatures. We find that in a CH plasma, beam intersection leads to about a factor of 2 increase in the SRS from the 351 nm beam compared to no intersection. Beam intersection does not change the SBS backscattering level studied with a CO2 plasma. We describe the experimental results and simulations using the LASNEX hydrodynamic code and the pF3D laser-plasma wave propagation code. Work performed under the auspicies of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under contract number W--7405--ENG--48.

  9. Performance of a high-NA dual-stage 193-nm TWINSCAN Step and Scan system for 80-nm applications

    NASA Astrophysics Data System (ADS)

    de Klerk, Jos; Jorritsma, Louis; van Setten, Eelco; Droste, Richard; du Croo de Jongh, Richard; Hansen, Steven G.; Smith, Dan; van de Kerkhof, Mark A.; van de Mast, Frank; Graeupner, Paul; Rohe, Thomas; Kornitzer, Klaus

    2003-06-01

    As the semiconductor industry looks into the near future to extend manufacturing beyond 100nm, a new optical lithography system was developed by ASML. To achieve the aggressive industry roadmap and enable high volume manufacturing of sub 100nm resolutions at low k1 requires a number of challenges to be overcome. This paper reviews the design, system performance and measurements of a High NA, Dual stage 193nm TWINSCAN system planned for high volume manufacturing for 80nm applications. The overall system capability to effectively measure and control to a high precision the various attributes upon process control necessary for adequate CD control, in the low k1 regime will be shown. This paper will discuss the needed imaging control and the requirement for an extremely stable and matured platform. The system's dynamic, focus, leveling and dose delivery performance will be shown. Additionally, the automated control features of the optical system will be shown that enable the use of the various resolution enhancement techniques (RET) currently under development. The ability to optimize imaging performance with the control and flexibility in the pupil formation optics will be discussed. Finally, experimental results of an in-situ measurement technique with automated feedback control to optimize projection lens aberrations, which has a direct impact to imaging fidelity, will be shown. In summary, the lithographic system functionality and performance needed to achieve 80nm volume manufacturing will be presented.

  10. Extension of 193 nm dry lithography to 45-nm half-pitch node: double exposure and double processing technique

    NASA Astrophysics Data System (ADS)

    Biswas, Abani M.; Li, Jianliang; Hiserote, Jay A.; Melvin, Lawrence S., III

    2006-10-01

    Immersion lithography and multiple exposure techniques are the most promising methods to extend lithography manufacturing to the 45nm node. Although immersion lithography has attracted much attention recently as a promising optical lithography extension, it will not solve all the problems at the 45-nm node. The 'dry' option, (i.e. double exposure/etch) which can be realized with standard processing practice, will extend 193-nm lithography to the end of the current industry roadmap. Double exposure/etch lithography is expensive in terms of cost, throughput time, and overlay registration accuracy. However, it is less challenging compared to other possible alternatives and has the ability to break through the κ I barrier (0.25). This process, in combination with attenuated PSM (att-PSM) mask, is a good imaging solution that can reach, and most likely go beyond, the 45-nm node. Mask making requirements in a double exposure scheme will be reduced significantly. This can be appreciated by the fact that the separation of tightly-pitched mask into two less demanding pitch patterns will reduce the stringent specifications for each mask. In this study, modeling of double exposure lithography (DEL) with att-PSM masks to target 45-nm node is described. In addition, mask separation and implementation issues of optical proximity corrections (OPC) to improve process window are studied. To understand the impact of OPC on the process window, Fourier analysis of the masks has been carried out as well.

  11. Three-body dissociations: The photodissociation of dimethyl sulfoxide at 193 nm

    SciTech Connect

    Blank, D.A.; North, S.W.; Stranges, D.

    1997-04-01

    When a molecule with two equivalent chemical bonds is excited above the threshold for dissociation of both bonds, how the rupture of the two bonds is temporally coupled becomes a salient question. Following absorption at 193 nm dimethyl sulfoxide (CH{sub 3}SOCH{sub 3}) contains enough energy to rupture both C-S bonds. This can happen in a stepwise (reaction 1) or concerted (reaction 2) fashion where the authors use rotation of the SOCH{sub 3} intermediate prior to dissociation to define a stepwise dissociation: (1) CH{sub 3}SOCH{sub 3} {r_arrow} 2CH{sub 3} + SO; (2a) CH{sub 3}SOCH{sub 3} {r_arrow} CH{sub 3} + SOCH{sub 3}; and (2b) SOCH{sub 3} {r_arrow} SO + CH{sub 3}. Recently, the dissociation of dimethyl sulfoxide following absorption at 193 nm was suggested to involve simultaneous cleavage of both C-S bonds on an excited electronic surface. This conclusion was inferred from laser induced fluorescence (LIF) and resonant multiphoton ionization (2+1 REMPI) measurements of the internal energy content in the CH{sub 3} and SO photoproducts and a near unity quantum yield measured for SO. Since this type of concerted three body dissociation is very interesting and a rather rare event in photodissociation dynamics, the authors chose to investigate this system using the technique of photofragment translational spectroscopy at beamline 9.0.2.1. The soft photoionization provided by the VUV undulator radiation allowed the authors to probe the SOCH{sub 3} intermediate which had not been previously observed and provided good evidence that the dissociation of dimethyl sulfoxide primarily proceeds via a two step dissociation, reaction 2.

  12. Imaging challenges in 20nm and 14nm logic nodes: hot spots performance in Metal1 layer

    NASA Astrophysics Data System (ADS)

    Timoshkov, V.; Rio, D.; Liu, H.; Gillijns, W.; Wang, J.; Wong, P.; Van Den Heuvel, D.; Wiaux, V.; Nikolsky, P.; Finders, J.

    2013-10-01

    The 20nm Metal1 layer, based on ARM standard cells, has a 2D design with minimum pitch of 64nm. This 2D design requires a Litho-Etch-Litho-Etch (LELE) double patterning. The whole design is divided in 2 splits: Me1A and Me1B. But solution of splitting conflicts needs stitching at some locations, what requires good Critical Dimension (CD) and overlay control to provide reliable contact between 2 stitched line ends. ASML Immersion NXT tools are aimed at 20 and 14nm logic production nodes. Focus control requirements become tighter, as existing 20nm production logic layouts, based on ARM, have about 50-60nm focus latitude and tight CD Uniformity (CDU) specifications, especially for line ends. IMEC inspected 20nm production Metal1 ARM standard cells with a Negative Tone Development (NTD) process using the Process Window Qualification-like technique experimentally and by Brion Tachyon LMC by simulations. Stronger defects were found thru process variations. A calibrated Tachyon model proved a good overall predictability capability for this process. Selected defects are likely to be transferred to hard mask during etch. Further, CDU inspection was performed for these critical features. Hot spots showed worse CD uniformity than specifications. Intra-field CDU contribution is significant in overall CDU budget, where reticle has major impact due to high MEEF of hot spots. Tip-to-Tip and tip-to-line hot spots have high MEEF and its variation over the field. Best focus variation range was determined by best focus offsets between hot spots and its variation within the field.

  13. Coherent 455 nm beam production in a cesium vapor.

    PubMed

    Schultz, J T; Abend, S; Döring, D; Debs, J E; Altin, P A; White, J D; Robins, N P; Close, J D

    2009-08-01

    We observe coherent, cw, 455 nm blue-beam production via frequency upconversion in cesium vapor. Two IR lasers induce strong double excitation in a heated cesium vapor cell, allowing the atoms to undergo a double cascade and produce a coherent, collimated, blue beam copropagating with the two IR pump lasers.

  14. 77 FR 62481 - Radio Broadcasting Services; Crownpoint, NM

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-15

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Crownpoint, NM AGENCY: Federal Communications....415 and 1.420. List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications... preamble, the Federal Communications Commission proposes to amend 47 CFR Part 73 as follows: PART...

  15. 78 FR 72141 - New Mexico Disaster Number NM-00037

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-02

    ... ADMINISTRATION New Mexico Disaster Number NM-00037 AGENCY: U.S. Small Business Administration. ACTION: Amendment... Assistance Only for the State of New Mexico (FEMA-4148-DR), dated 09/30/2013. Incident: Severe Storms and... Private Non-Profit organizations in the State of New Mexico, dated 09/30/2013, is hereby amended...

  16. 77 FR 55523 - New Mexico Disaster #NM-00029

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-10

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION New Mexico Disaster NM-00029 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of New Mexico (FEMA- 4079-DR), dated 08/24/2012. Incident: Flooding. Incident Period:...

  17. 78 FR 61999 - New Mexico Disaster #NM-00037

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-10

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION New Mexico Disaster NM-00037 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of New Mexico (FEMA- 4148-DR), dated 09/30/2013. Incident: Severe Storms and Flooding....

  18. 75 FR 57538 - New Mexico Disaster # NM-00016

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-21

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION New Mexico Disaster NM-00016 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of New Mexico (FEMA- 1936-DR), dated 09/13/2010. Incident: Severe Storms and Flooding....

  19. 76 FR 81553 - New Mexico Disaster Number NM-00024

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-28

    ... ADMINISTRATION New Mexico Disaster Number NM-00024 AGENCY: U.S. Small Business Administration. ACTION: Amendment... Assistance Only for the State of New Mexico (FEMA-4047-DR), dated 11/23/2011. Incident: Flooding. Incident... Non-Profit organizations in the State of New Mexico, dated 11/23/2011, is hereby amended to...

  20. 77 FR 63409 - New Mexico Disaster Number NM-00029

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-16

    ... ADMINISTRATION New Mexico Disaster Number NM-00029 AGENCY: U.S. Small Business Administration. ACTION: Amendment... Assistance Only for the State of New Mexico (FEMA-4079-DR), dated 08/24/2012. Incident: Flooding. Incident... Non-Profit organizations in the State of NEW MEXICO, dated 08/24/2012, is hereby amended to...

  1. 78 FR 73581 - New Mexico Disaster Number NM-00035

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-06

    ... ADMINISTRATION New Mexico Disaster Number NM-00035 AGENCY: U.S. Small Business Administration. ACTION: Amendment... Assistance Only for the State of New Mexico (FEMA-4152-DR), dated 10/29/2013. Incident: Severe Storms... disaster declaration for Private Non-Profit organizations in the State of New Mexico, dated 10/29/2013,...

  2. 76 FR 2431 - New Mexico Disaster #NM-00016

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-13

    ... ADMINISTRATION New Mexico Disaster NM-00016 AGENCY: U.S. Small Business Administration. ACTION: Amendment 1... Only for the State of New Mexico (FEMA-1936-DR), dated 09/13/2010. Incident: Severe Storms and Flooding... Private Non-Profit organizations in the State of NEW MEXICO, dated 09/13/2010, is hereby amended...

  3. 76 FR 18289 - New Mexico Disaster #NM-00020

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-01

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION New Mexico Disaster NM-00020 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of New Mexico (FEMA- 1962-DR), dated 03/24/2011. Incident: Severe Winter Storm and Extreme...

  4. 78 FR 66982 - New Mexico Disaster #NM-00035

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-07

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION New Mexico Disaster NM-00035 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of New Mexico (FEMA- 4152-DR), dated 10/29/2013. Incident: Severe storms, flooding, and...

  5. 77 FR 41874 - New Mexico Disaster #NM-00025

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-16

    ... ADMINISTRATION New Mexico Disaster NM-00025 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of New Mexico dated 07/09/2012. Incident: Little Bear Fire. Incident Period: 06/04/2012 and continuing. Effective Date:...

  6. 77 FR 47907 - New Mexico Disaster #NM-00025

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-10

    ... ADMINISTRATION New Mexico Disaster NM-00025 AGENCY: U.S. Small Business Administration. ACTION: Amendment 1. SUMMARY: This is an amendment of the Administrative declaration of a disaster for the State of NEW MEXICO, dated 07/09/2012. Incident: Little Bear Fire. Incident Period: 06/04/2012 through 07/30/2012....

  7. EUV optical design for 100 nm CD imaging system

    SciTech Connect

    Sweeney, D.W.; Hudyma, R.; Chapman, H.B.; Shafer, D.

    1998-04-09

    The imaging specifications for extreme ultraviolet lithography (EUVL) projection optics parallel those of other optical lithographies. Specifications are scaled to reflect the 100 nm critical dimension for the first generation EUVL systems. The design being fabricated for the Engineering Test Stand, an EUVL alpha tool, consists of a condenser with six channels to provide an effective partial coherence factor of 0.7. The camera contains four mirrors; three of the mirrors are aspheres and the fourth is spherical. The design of the optical package has been constrained so that the angles of incidence and the variations in the angle of incidence of all rays allow for uniform multilayer coatings. The multilayers introduce a slight shift in image position and magnification. We have shown that a system aligned with visible light is also aligned at 13.4 nm. Each mirror must be fabricated with an RMS figure error of less than 0.25 nm and better than 0.2 nm RMS roughness. Optical surfaces that exceed each of these specifications individually have been fabricated. The success of EUVL requires that these specifications be met simultaneously.

  8. Microstructure of 100 nm damascene copper overburden and lines

    NASA Astrophysics Data System (ADS)

    Geiss, R. H.; Read, D. T.

    2007-09-01

    A detailed understanding of the crystallography of metallic conductors in modern interconnect systems is essential if we are to understand the influence of processing parameters on performance and reliability. In particular we must be able to evaluate the grain size, crystallographic orientation and residual elastic stress for interconnect lines having widths of tens of nm. Transmission electron microscopy might be the obvious choice, but sample preparation and small sample size make this technique unattractive. On the other hand, electron backscatter diffraction, EBSD, in a scanning electron microscope provides a very attractive tool. Sample preparation can be relatively simple, especially if one investigates the structures immediately after CMP; whole wafers may be measured if desired. One limitation to EBSD is that good diffraction patterns are obtained only from free surfaces and from a limited depth, say a few hundred nm in copper. Here EBSD will be used to compare structures for the pads and 100-nm lines in two variants of a commercial copper damascene interconnect structure. EBSD data collection will be discussed as optimized for characterizing differences in the texture, which were attributed to differences in the processing. By a unique approach to EBSD mapping we found that neither the texture nor the grain size of the overburden, as represented by the contact pads, propagated into the 100 nm lines, though they did propagate into some wider lines.

  9. The Photochemistry of Cyano and Dicyanoacetylene at 193 nm.

    DTIC Science & Technology

    1987-07-28

    Halpern, L. Petway , R. Lu, W.M. Jackson, and V.R. McCrary and W. Nottingham Prepared for submission to the Journal of Chemical Physics Department of...CYANO- AND DICYANOACETYLENE AT 193 NM By J. B. Halpern% L. Petway , R. Lu W. M. Jackson , and V. R. McCrary Department of Chemistry Howard University

  10. 78 FR 66982 - Santa Clara Pueblo Disaster #NM-00039

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-07

    ... ADMINISTRATION Santa Clara Pueblo Disaster NM-00039 AGENCY: U.S. Small Business Administration. ACTION: Notice... for the Santa Clara Pueblo (FEMA- 4151-DR), dated 10/29/2013. Incident: Severe Storms and Flooding... disaster: Primary Areas: Santa Clara Pueblo. The Interest Rates are: Percent For Physical Damage:...

  11. High average power, narrow band 248 nm alexandrite laser system

    SciTech Connect

    Kuper, J.W.; Chin, T.C.; Papanestor, P.A.

    1994-12-31

    A compact line-narrowed 248 nm solid state laser source operating at 15 mJ {at} 100 Hz PRF was demonstrated. Constraints due to thermal loading of components were addressed. Tradeoffs between pulse energy and repetition rate were investigated. A method for overcoming thermal dephasing in the THG material was achieved by scanning a slab shaped crystal.

  12. Holographic voltage profiling on 75 nm gate architecture CMOS devices.

    PubMed

    Thesen, Alexander E; Frost, Bernhard G; Joy, David C

    2003-04-01

    Voltage profiles of the source-drain region of a CMOS transistor with 75nm gate architecture taken from an off-the-shelf Intel PIII processor are presented. The sample preparation using a dual beam system is discussed as well as details of the electron optical setup of the microscope. Special attention is given to the analysis of the reconstructed holograms.

  13. A novel double patterning approach for 30nm dense holes

    NASA Astrophysics Data System (ADS)

    Hsu, Dennis Shu-Hao; Wang, Walter; Hsieh, Wei-Hsien; Huang, Chun-Yen; Wu, Wen-Bin; Shih, Chiang-Lin; Shih, Steven

    2011-04-01

    Double Patterning Technology (DPT) was commonly accepted as the major workhorse beyond water immersion lithography for sub-38nm half-pitch line patterning before the EUV production. For dense hole patterning, classical DPT employs self-aligned spacer deposition and uses the intersection of horizontal and vertical lines to define the desired hole patterns. However, the increase in manufacturing cost and process complexity is tremendous. Several innovative approaches have been proposed and experimented to address the manufacturing and technical challenges. A novel process of double patterned pillars combined image reverse will be proposed for the realization of low cost dense holes in 30nm node DRAM. The nature of pillar formation lithography provides much better optical contrast compared to the counterpart hole patterning with similar CD requirements. By the utilization of a reliable freezing process, double patterned pillars can be readily implemented. A novel image reverse process at the last stage defines the hole patterns with high fidelity. In this paper, several freezing processes for the construction of the double patterned pillars were tested and compared, and 30nm double patterning pillars were demonstrated successfully. A variety of different image reverse processes will be investigated and discussed for their pros and cons. An economic approach with the optimized lithography performance will be proposed for the application of 30nm DRAM node.

  14. Gain measurements at 5 nm in nickel-like ytterbium

    SciTech Connect

    MacGowan, B.J.; Bourgade, J.L.; Combis, P.; Keane, C.J.; Louis-Jacquet, M.; Matthews, D.L.; Naccache, D.; Stone, G.; Thiell, G.; Whelan, D.A.

    1988-03-01

    Soft x-ray gain has been demonstrated at 5.03 nm within a laser produced plasma of Ni-like ytterbium. Experiments will also be described with higher Z Ni-like ions which can produce even shorter wavelength x-ray laser transition. 3 refs.

  15. 78 FR 67210 - Santa Clara Pueblo Disaster #NM-00038

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-08

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Santa Clara Pueblo Disaster NM-00038 AGENCY: U.S. Small Business Administration. ACTION: Notice...: Submit completed loan applications to: U.S. Small Business Administration, Processing and...

  16. EPA Sparks Local Business in Las Cruces, N.M.

    EPA Pesticide Factsheets

    DALLAS - (Feb. 29, 2016) The U.S. Environmental Protection Agency (EPA) is awarding a $300,000 small business contract to Vista Photonics, Inc. in Las Cruces, N.M. The company plans to develop an inexpensive, high-performance, portable air pollution

  17. Blue light (470 nm) effectively inhibits bacterial and fungal growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The activity of blue light (470nm) alone on (1) bacterial viability, and (2) with a food grade photosensitizer on filamentous fungal viability, was studied. Suspensions of the bacteria Leuconostoc mesenteroides (LM), Bacillus atrophaeus (BA), and Pseudomonas aeruginosa (PA) were prepared and aliquo...

  18. Pushing EUV lithography development beyond 22-nm half pitch

    SciTech Connect

    Naulleau, Patrick; Anderson, Christopher N.; Baclea-an, Lorie-Mae; Denham, Paul; George, Simi; Goldberg, Kenneth A.; Goldstein, Michael; Hoef, Brian; Jones, Gideon; Koh, Chawon; La Fontaine, Bruno; Montogomery, Warren; Wallow, Tom

    2009-06-30

    Microfield exposure tools (METs) have and continue to play a dominant role in the development of extreme ultraviolet (EUV) resists and masks. One of these tools is the SEMATECH Berkeley 0.3 numerical aperture (NA) MET. Here we investigate the possibilities and limitations of using the 0.3-NA MET for sub-22-nm half-pitch development. We consider mask resolution limitations and present a method unique to the centrally obscured MET allowing these mask limitations to be overcome. We also explore projection optics resolution limits and describe various illumination schemes allowing resolution enhancement. At 0.3-NA, the 0.5 k1 factor resolution limit is 22.5 nm meaning that conventional illumination is of limited utility for sub-22-nm development. In general resolution enhancing illumination encompasses increased coherence. We study the effect of this increased coherence on line-edge roughness, which along with resolution is another crucial factor in sub-22-nm resist development.

  19. 76 FR 22015 - Amendment of Class E Airspace; Raton, NM

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-20

    ... Municipal Airport/Crews Field, Raton, NM. The FAA is taking this action to enhance the safety and management... additional controlled airspace at Raton Municipal Airport/ Crews Field (76 FR 5305) Docket No. FAA-2010-1239... accommodate new RNAV standard instrument approach procedures at Raton Municipal Airport/Crews Field, Raton,...

  20. O(1)S 557.7nm and O(1)D 630 nm emissions in shuttle thruster plumes

    NASA Technical Reports Server (NTRS)

    Viereck, R. A.; Murad, E.; Pike, C. P.; Mende, S. B.; Swenson, G. A.; Elgin, J. B.; Bernstein, L. S.; Lucid, S.

    1995-01-01

    Radiation resulting from interaction between the effluent cloud of a space shuttle thruster and the ambient atmosphere was observed with a spectograph aboard the shutttle. The spectral measurements were made between 400 and 800 nm with a resolutoion of 3 nm. The primary emissions are identified as NO2, HNO, O(1)D, and O(1)S. These are the first observations od O(1)S emission in the shuttle plume. These data are compared with the previous measurements, and possible excitation mechanisms are discussed. The results are also compared with a Monte Carlo simulation of thruster plume-atmosphere interaction radiation.

  1. Center and limb solar spectrum in high spectral resolution 225.2 nm to 319.6 nm

    NASA Technical Reports Server (NTRS)

    Kohl, J. L.; Parkinson, W. H.; Kurucz, R. L.

    1978-01-01

    The atlas has been designed to fulfill the need in solar and stellar astronomy, in aeronomy, and in space science for a convenient reference source that provides a detailed and accurate record of the measured solar ultraviolet spectrum in high spectral resolution for the wavelength range from 225.2 nm to 319.6 nm. The atlas also contains a preliminary synthetic solar spectrum with a legend for identifying and describing the features of the synthetic spectrum. Attention is given to aspects of instrumentation, the radiometric calibration, the wavelength scale, background noise random fluctuations and data filtering, intermittent noise, the observational conditions, the experimental uncertainty, the atlas format, references, tables, and plots.

  2. Size control in the synthesis of 1-6 nm gold nanoparticles using folic acid-chitosan conjugate as a stabilizer

    NASA Astrophysics Data System (ADS)

    Liu, Lili; Zhang, Xianwen; Chaudhuri, Jharna

    2014-09-01

    We report a simple and practical method for the preparation of folic acid (FA)-chitosan functionalized gold nanoparticles (AuNPs) with a very small size (1-6 nm). Sodium borohydride was used as a reducing agent. The size of the AuNPs was controlled by adjusting the mass fraction of FA-chitosan conjugate to Au. The AuNPs were characterized using UV-vis spectroscopy and transmission electron microscopy (TEM). The results indicated that the size distribution of AuNPs decreased ranging from 6 nm to 1 nm with increasing the fraction of FA-chitosan conjugate in the reaction systems.

  3. Kinetic analysis of the hydrolysis of methyl parathion using citrate-stabilized 10 nm gold nanoparticles.

    PubMed

    Nita, Rafaela; Trammell, Scott A; Ellis, Gregory A; Moore, Martin H; Soto, Carissa M; Leary, Dagmar H; Fontana, Jake; Talebzadeh, Somayeh F; Knight, D Andrew

    2016-02-01

    "Ligand-free" citrate-stabilized 10 nm gold nanoparticles (AuNPs) promote the hydrolysis of the thiophosphate ester methyl parathion (MeP) on the surface of gold as a function of pH and two temperature values. At 50 °C, the active surface gold atoms show catalytic turnover ∼4 times after 8 h and little turnover of gold surface atoms at 25 °C with only 40% of the total atoms being active. From Michaelis-Menten analysis, k(cat) increases between pH 8 and 9 and decreases above pH 9. A global analysis of the spectral changes confirmed the stoichiometric reaction at 25 °C and the catalytic reaction at 50 °C and mass spectrometry confirmed the identity of p-nitrophenolate (PNP) product. Additional decomposition pathways involving oxidation and hydrolysis independent of the formation of PNP were also seen at 50 °C for both catalyzed and un-catalyzed reactions. This work represents the first kinetic analysis of ligand-free AuNP catalyzed hydrolysis of a thiophosphate ester.

  4. Microscale Thermite Reactions.

    ERIC Educational Resources Information Center

    Arnaiz, Francisco J.; Aguado, Rafael; Arnaiz, Susana

    1998-01-01

    Describes the adaptation of thermite (aluminum with metal oxides) reactions from whole-class demonstrations to student-run micro-reactions. Lists detailed directions and possible variations of the experiment. (WRM)

  5. Microfluidic chemical reaction circuits

    SciTech Connect

    Lee, Chung-cheng; Sui, Guodong; Elizarov, Arkadij; Kolb, Hartmuth C; Huang, Jiang; Heath, James R; Phelps, Michael E; Quake, Stephen R; Tseng, Hsian-rong; Wyatt, Paul; Daridon, Antoine

    2012-06-26

    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  6. Allergic reactions (image)

    MedlinePlus

    Allergic reaction is a sensitivity to a specific substance, called an allergen, that is contacted through the skin, inhaled into the lungs, swallowed or injected. The body's reaction to an allergen can be mild, such as ...

  7. Allergic reactions (image)

    MedlinePlus

    Allergic reaction can be provoked by skin contact with poison plants, chemicals and animal scratches, as well as by ... dust, nuts and shellfish, may also cause allergic reaction. Medications such as penicillin and other antibiotics are ...

  8. Study of drain-extended NMOS under electrostatic discharge stress in 28 nm and 40 nm CMOS process

    NASA Astrophysics Data System (ADS)

    Wang, Weihuai; Jin, Hao; Dong, Shurong; Zhong, Lei; Han, Yan

    2016-02-01

    Researches on the electrostatic discharge (ESD) performance of drain-extended NMOS (DeNMOS) under the state-of-the-art 28 nm and 40 nm bulk CMOS process are performed in this paper. Three distinguishing phases of avalanche breakdown stage, depletion region push-out stage and parasitic NPN turn on stage of the gate-grounded DeNMOS (GG-DeNMOS) fabricated under 28 nm CMOS process measured with transmission line pulsing (TLP) test are analyzed through TCAD simulations and tape-out silicon verification detailedly. Damage mechanisms and failure spots of GG-DeNMOS under both CMOS processes are thermal breakdown of drain junction. Improvements based on the basic structure adjustments can increase the GG-DeNMOS robustness from original 2.87 mA/μm to the highest 5.41 mA/μm. Under 40 nm process, parameter adjustments based on the basic structure have no significant benefits on the robustness improvements. By inserting P+ segments in the N+ implantation of drain or an entire P+ strip between the N+ implantation of drain and polysilicon gate to form the typical DeMOS-SCR (silicon-controlled rectifier) structure, the ESD robustness can be enhanced from 1.83 mA/μm to 8.79 mA/μm and 29.78 mA/μm, respectively.

  9. Cryogenic Lifetime Studies of 130 nm and 65 nm CMOS Technologies for High-Energy Physics Experiments

    SciTech Connect

    Hoff, James R.; Deptuch, G. W.; Wu, Guoying; Gui, Ping

    2015-06-04

    The Long Baseline Neutrino Facility intends to use unprecedented volumes of liquid argon to fill a time projection chamber in an underground facility. Research is under way to place the electronics inside the cryostat. For reasons of efficiency and economics, the lifetimes of these circuits must be well in excess of 20 years. The principle mechanism for lifetime degradation of MOSFET devices and circuits operating at cryogenic temperatures is hot carrier degradation. Choosing a process technology that is, as much as possible, immune to such degradation and developing design techniques to avoid exposure to such damage are the goals. This, then, requires careful investigation and a basic understanding of the mechanisms that underlie hot carrier degradation and the secondary effects they cause in circuits. In this work, commercially available 130 nm and 65 nm nMOS transistors operating at cryogenic temperatures are investigated. Our results show that both technologies achieve the lifetimes required by the experiment. Minimal design changes are necessary in the case of the 130 nm process and no changes whatsoever are necessary for the 65 nm process.

  10. Barometric coefficients for different neutron multiplicities according to ESA NM data (Israel) and data of University "Roma Tre" NM (Italy)

    NASA Astrophysics Data System (ADS)

    Dorman, L. I.; Iucci, N.; Sternlieb, A.; Villoresi, G.; Zukermann, I. G.

    2001-08-01

    On the basis of hourly data obtained by neutron monitor (NM) of Emilio Segre' Observatory (height 2025 ma bove s. l., cut-off rigidity for vertical direction 10.8 GV) and by NM of University "Roma Tre" (about sea level, cutoff rigidity 6.7 GV) we determine barometric coefficients both stations for total neutron intensity and for multiplicities m ≥ 1, m ≥ 2, m ≥ 3, m ≥ 4, m ≥ 5, m ≥ 6, m ≥ 7,a nd m ≥ 8, as well as for m=1, m=2, m=3, m=4, m=5, m=6,a nd m=7. We determine also for each hour the effective multiplicity for m ≥ 8 and estimate the barometricc oefficient for for both NM sections. We used hourly data from June 1998 up to April 2001, and we excludedp eriods when above the NM of Emilio Segre' Observatoryw as snow. We compare obtained results with expected according to the theory of meteorological effects for totaln eutron component and for neutron multiplicities.

  11. Final report on the torque key komparison CCM.T-K1.2 measurand torque: 0 N.m, 500 N.m, 1000 N.m

    NASA Astrophysics Data System (ADS)

    Röske, Dirk

    2015-01-01

    The purpose of the CIPM subsequent bilateral comparison CCM.T-K1.2 was to link another participant, namely the National Institute of Metrology (Thailand), in short NIMT, to the CCM.T-K1 torque key comparison. The measuring capabilities up to 1000 N.m of dead-weight torque standard machines with supported lever were investigated. The pilot laboratory was the same in both comparisons—it was the Physikalisch-Technische Bundesanstalt (PTB, Braunschweig, Germany). The same two very stable torque transducers with well-known properties were used as travelling standards. The measurements at the participating laboratory were carried out between November 2007 and February 2008. According to the technical protocol, torque steps of 500 N.m and 1000 N.m had to be measured both in clockwise and anticlockwise directions. Corrections had to be applied to the results reported by the participants taking into account the use of different amplifiers, the creep (due to different loading times of the machines) and the environmental conditions in the laboratories (temperature and relative humidity of the ambient air). The results of the pilot laboratory in this bilateral comparison are in very good agreement with the same results obtained in the CCM.T-K1 comparison. For each of the transducers, the two torque steps and both senses of direction of the torque vector, the key comparison reference value of the CCM.T-K1 was taken, and the results of participant NIMT were calculated with respect to these values. The agreement between the results is very good. The smallest expanded (k = 2) relative uncertainty of the machine stated by the participant is 1 × 10-4. The results of the comparison support this uncertainty statement. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by CCM, according

  12. Direct writing of 150 nm gratings and squares on ZnO crystal in water by using 800 nm femtosecond laser.

    PubMed

    Liu, Jukun; Jia, Tianqing; Zhou, Kan; Feng, Donghai; Zhang, Shian; Zhang, Hongxin; Jia, Xin; Sun, Zhenrong; Qiu, Jianrong

    2014-12-29

    We present a controllable fabrication of nanogratings and nanosquares on the surface of ZnO crystal in water based on femtosecond laser-induced periodic surface structures (LIPSS). The formation of nanogrooves depends on both laser fluence and writing speed. A single groove with width less than 40 nm and double grooves with distance of 150 nm have been produced by manipulating 800 nm femtosecond laser fluence. Nanogratings with period of 150 nm, 300 nm and 1000 nm, and nanosquares with dimensions of 150 × 150 nm2 were fabricated by using this direct femtosecond laser writing technique.

  13. Nonresonant 104 Terahertz Field Enhancement with 5-nm Slits

    PubMed Central

    Suwal, Om Krishna; Rhie, Jiyeah; Kim, Nayeon; Kim, Dai-Sik

    2017-01-01

    Transmission of Terahertz (THz) electromagnetic wave through a substrate is encumbered because of scattering, multiple reflections, absorption, and Fabry–Perot effects when the wave interacts with the substrate. We present the experimental realization of nonresonant electromagnetic field enhancement by a factor of almost 104 in substrate-free 5-nm gold nanoslits. Our nanoslits yielded greater than 90% normalized electric field transmission in the low-frequency THz region; the slit width was 5 nm, and the gap coverage ratio was 10−4 of the entire membrane, 0.42 mm2. This large field enhancement was attributed to gap plasmons generated by the THz wave, which squeezes the charge cross-section, thus enabling very highly dense oscillating charges and strong THz field transmission from the nanoslits. PMID:28368048

  14. Experimental study of 248nm excimer laser etching of alumina

    NASA Astrophysics Data System (ADS)

    Hu, Hongtao; Shao, Jingzhen; Wang, Xi; Fang, Xiaodong

    2016-10-01

    The 248 nm excimer laser etching characteristic of alumina ceramic and sapphire had been studied using different laser fluence and different number of pulses. And the interaction mechanism of 248 nm excimer laser with alumina ceramic and sapphire had been analyzed. The results showed that when the laser fluence was less than 8 J/cm2, the etching depth of alumina ceramic and sapphire were increased with the increase of laser fluence and number of pulses. At the high number pulses and high-energy, the surface of the sapphire had no obvious melting phenomenon, and the alumina ceramic appeared obvious melting phenomenon. The interaction mechanism of excimer laser with alumina ceramics and sapphire was mainly two-photon absorption. But because of the existence of impurities and defects, the coupling between the laser radiation and ceramic and sapphire was strong, and the thermal evaporation mechanism was also obvious.

  15. A 20 nm spin Hall nano-oscillator.

    PubMed

    Dürrenfeld, Philipp; Awad, Ahmad A; Houshang, Afshin; Dumas, Randy K; Åkerman, Johan

    2017-01-19

    Spin Hall nano-oscillators (SHNOs) are an emerging class of pure spin current driven microwave signal generators. Through the fabrication of 20 nm nano-constrictions in Pt/NiFe bilayers, we demonstrate that SHNOs can be scaled down to truly nanoscopic dimensions, with the added benefit of ultra-low operating currents and improved power conversion efficiency. The lateral confinement leads to a strong shape anisotropy field as well as an additional demagnetizing field whose reduction with increasing auto-oscillation amplitude can yield a positive current tunability contrary to the negative tunability commonly observed for localized excitations in extended magnetic layers. Micromagnetic simulations corroborate the experimental findings and suggest that the active magnetodynamic area resides up to 100 nm outside of the nano-constriction.

  16. Single, composite, and ceramic Nd:YAG 946-nm lasers

    NASA Astrophysics Data System (ADS)

    Lan, Rui-Jun; Yang, Guang; Zheng-Ping, Wang

    2015-06-01

    Single, composite crystal and ceramic continuous wave (CW) 946-nm Nd:YAG lasers are demonstrated, respectively. The ceramic laser behaves better than the crystal laser. With 5-mm long ceramic, a CW output power of 1.46 W is generated with an optical conversion efficiency of 13.9%, while the slope efficiency is 17.9%. The optimal ceramic length for a 946-nm laser is also calculated. Project supported by the National Natural Science Foundation of China (Grant No. 61405171), the Natural Science Foundation of Shandong Province, China (Grant No. ZR2012FQ014), and the Science and Technology Program of the Shandong Higher Education Institutions of China (Grant No. J13LJ05).

  17. Sub-5 nm, globally aligned graphene nanoribbons on Ge(001)

    DOE PAGES

    Kiraly, Brian; Mannix, Andrew J.; Jacobberger, Robert M.; ...

    2016-05-23

    Graphene nanoribbons (GNRs) hold great promise for future electronics because of their edge and width dependent electronic bandgaps and exceptional transport properties. While significant progress toward such devices has been made, the field has been limited by difficulties achieving narrow widths, global alignment, and atomically pristine GNR edges on technologically relevant substrates. A recent advance has challenged these limits by using Ge(001) substrates to direct the bottom-up growth of GNRs with nearly pristine armchair edges and widths near ~10 nm via atmospheric pressure chemical vapor deposition. In this work, we extend the growth of GNRs on Ge(001) to ultra-high vacuummore » conditions and realize GNRs narrower than 5 nm. Armchair graphene nanoribbons directed along the Ge <110> surface directions are achieved with excellent width control and relatively large bandgaps. As a result, the bandgap magnitude and electronic uniformity make these new materials excellent candidates for future developments in nanoelectronics.« less

  18. Machining of optical microstructures with 157 nm laser radiation

    NASA Astrophysics Data System (ADS)

    Temme, Thorsten; Ostendorf, Andreas; Kulik, Christian J.

    2003-11-01

    The precision machining of glass by laser ablation has been expanded with the short wavelength of the 157 nm of the F2 excimer laser. The high absorption of this wavelength in any optical glass, especially in UV-grade fused silica, offers a new approach to generate high quality surfaces, addressing also micro-optical components. In this paper, the machining of basic diffractive and refractive optical components and the required machining and process technology is presented. Applications that are addressed are cylindrical and rotational symmetrical micro lenses and diffractive optics like phase transmission grating and diffractive optical elements (DOEs). These optical surfaces have been machined into bulk material as well as on fiber end surfaces, to achieve compact (electro) -- optical elements with high functionality and packaging density. The short wavelength of 157 nm used in the investigations require either vacuum or high purity inert gas environments. The influence of different ambient conditions is presented.

  19. Performance of Thin Borosilicate Glass Sheets at 351-nm

    SciTech Connect

    Whitman, P K; Hahn, D; Soules, T; Norton, M; Dixit, S; Donohue, G; Folta, J; Hollingsworth, W; Mainschein-Cline, M

    2004-11-11

    Previously, we reported preliminary results for commercial thin borosilicate glass sheets evaluated for use as a frequently-replaced optic to separate the radiation and contamination produced by the inertial confinement fusion experiments in the National Ignition Facility target chamber from the expensive precision laser optics which focus and shape the 351-nm laser beam. The goal is identification of low cost substrates that can deliver acceptable beam energy and focal spots to the target. The two parameters that dominate the transmitted beam quality are the transmitted wave front error and 351-nm absorption. Commercial materials and fabrication processes have now been identified which meet the beam energy and focus requirements for all of the missions planned for the National Ignition Facility. We present the first data for use of such an optic on the National Ignition Facility laser.

  20. Sub-5 nm, globally aligned graphene nanoribbons on Ge(001)

    SciTech Connect

    Kiraly, Brian; Mannix, Andrew J.; Jacobberger, Robert M.; Fisher, Brandon L.; Arnold, Michael S.; Hersam, Mark C.; Guisinger, Nathan P.

    2016-05-23

    Graphene nanoribbons (GNRs) hold great promise for future electronics because of their edge and width dependent electronic bandgaps and exceptional transport properties. While significant progress toward such devices has been made, the field has been limited by difficulties achieving narrow widths, global alignment, and atomically pristine GNR edges on technologically relevant substrates. A recent advance has challenged these limits by using Ge(001) substrates to direct the bottom-up growth of GNRs with nearly pristine armchair edges and widths near ~10 nm via atmospheric pressure chemical vapor deposition. In this work, we extend the growth of GNRs on Ge(001) to ultra-high vacuum conditions and realize GNRs narrower than 5 nm. Armchair graphene nanoribbons directed along the Ge <110> surface directions are achieved with excellent width control and relatively large bandgaps. As a result, the bandgap magnitude and electronic uniformity make these new materials excellent candidates for future developments in nanoelectronics.

  1. Measured skin damage thresholds for 1314-nm laser exposures

    NASA Astrophysics Data System (ADS)

    Montes de Oca, Cecilia I.; Cain, Clarence P.; Schuster, Kurt J.; Stockton, Kevin; Thomas, James J.; Eggleston, Thomas A.; Roach, William P.

    2003-06-01

    The use of lasers in the infrared region between 1200-1400 nm has steadily increased in various industrial and commercial applications. However, there are few studies documenting damage thresholds for the skin in this region, and current laser safety standards are based on limited data. This study has determined preliminary skin damage thresholds for the Effective Dose for 50% probability (ED50) of a Minimum Visible Lesion (MVL) with laser exposure at 1314nm and 0.35 ms pulse width. An in-vivo pigmented animal model, Yucatan mini-pig (Sus scrofa domestica), was used in this study. The type and extent of tissue damage in the porcine skin was determined through histopathologic examination, and the findings are discussed. Finally, the results of this study were compared to other literature as well as to the existing ANSI Z136.1 (2000) standard for safe use of lasers.

  2. Preparation of sub-100-nm beta-lactoglobulin (BLG) nanoparticles.

    PubMed

    Ko, Sanghoon; Gunasekaran, Sundaram

    2006-12-01

    Sub-100-nm nanoparticles were prepared from beta-lactoglobulin (BLG) with a narrow size distribution by a desolvation method using glutaraldehyde for cross-linking. With pre-heating of the BLG solution to 60 degrees C and subsequent pH readjustment to 9.0, nanoparticles of 59 +/- 5 nm were obtained with improved uniformity. Bovine serum albumin (BSA) nanoparticles, prepared under similar conditions for comparison, were larger and less uniform. The half-width of 80% particle distribution was used to compare the uniformity of particle size distribution. The stability of the nanoparticles was investigated by degradation tests at neutral and acidic pHs with and without proteolytic enzymes, trypsin and pepsin. The degradation time, determined by a graphical approach, was used to compare the relative stabilities of BLG and BSA nanoparticles. The particles of BLG were more stable than those of BSA in acidic and neutral media with and without added enzymes.

  3. A deep-UV optical frequency comb at 205 nm.

    PubMed

    Peters, E; Diddams, S A; Fendel, P; Reinhardt, S; Hänsch, T W; Udem, Th

    2009-05-25

    By frequency quadrupling a picosecond pulse train from a Ti:sapphire laser at 820 nm we generate a frequency comb at 205 nm with nearly bandwidth-limited pulses. The nonlinear frequency conversion is accomplished by two successive frequency doubling stages that take place in resonant cavities that are matched to the pulse repetition rate of 82 MHz. This allows for an overall efficiency of 4.5 % and produces an output power of up to 70 mW for a few minutes and 25 mW with continuous operation for hours. Such a deep UV frequency comb may be employed for direct frequency comb spectroscopy in cases where it is less efficient to convert to these short wavelengths with continuous wave lasers.

  4. Thermotolerance of apple tree leaves probed by chlorophyll a fluorescence and modulated 820 nm reflection during seasonal shift.

    PubMed

    Duan, Ying; Zhang, Mengxia; Gao, Jin; Li, Pengmin; Goltsev, Vasilij; Ma, Fengwang

    2015-11-01

    During the seasonal shift from June to August, air temperatures increase. To explore how apple trees improve their thermotolerance during this shift, we examined the photochemical reaction capacity of apple tree leaves by simultaneous measurement of prompt chlorophyll fluorescence, delayed chlorophyll fluorescence, and modulated 820 nm reflection at varying temperatures. It was found that the reaction centers and antennae of photosystem II (PSII) and photosystem I (PSI), the donor side of PSII, the electron transfer capacity from QA to QB, and the reoxidation capacity of plastoquinol were all sensitive to heat stress, particularly in June. As the season shifted, apple tree leaves improved in thermotolerance. Interestingly, the acclimation to seasonal shift enhanced the thermotolerance of PSII and PSI reaction centers more than that of their antennae, and the activity of PSII more than that of PSI. This may be a strategy for plant adaptation to changes in environmental temperatures. In addition, results from prompt and delayed fluorescence, as well as modulated 820 nm reflection corroborate each other. We suggest that the simultaneous measurement of the three independent signals may provide more information on thermal acclimation mechanisms of photochemical reactions in plant leaves.

  5. Characterization of SAL605 negative resist at {lambda}=13 nm

    SciTech Connect

    La Fontaine, B.; Ciarlo, D.; Gaines, D.P.; Kania, D.R.

    1996-05-24

    We have characterized the response of the negative resist SAL605 in the extreme ultraviolet ({lambda}=13 nm). The sensitivity was found to be {approx}1 mJ/cm{sup 3} for all conditions studied. We have identified processing conditions leading to high ({gamma}{gt}4) contrast. The resist response was modeled using Prolith/2 and the development parameters were obtained from the exposure curves.

  6. Sub-nm emittance lattice design for CANDLE storage ring

    NASA Astrophysics Data System (ADS)

    Sargsyan, A.; Zanyan, G.; Sahakyan, V.; Tsakanov, V.

    2016-10-01

    The most effective way to increase the brilliance of synchrotron light sources is the reduction of beam emittance. Following the recent developments in low emittance lattice design, a new sub-nm emittance lattice based on implementation of multi-band achromat concept and application of longitudinal gradient bending magnets was developed for CANDLE storage ring. The paper presents the main design considerations, linear and non-linear beam dynamics aspects of the new lattice proposed.

  7. Excimer lasers for superhigh NA 193-nm lithography

    NASA Astrophysics Data System (ADS)

    Paetzel, Rainer; Albrecht, Hans S.; Lokai, Peter; Zschocke, Wolfgang; Schmidt, Thomas; Bragin, Igor; Schroeder, Thomas; Reusch, Christian; Spratte, Stefan

    2003-06-01

    Excimer lasers are widely used as the light source for microlithography scanners. The volume shipment of scanner systems using 193nm is projected to begin in year 2003. Such tools will directly start with super high numerical aperture (NA) in order to take full advantage of the 193nm wavelength over the advanced 248nm systems. Reliable high repetition rate laser light sources enabling high illumination power and wafer throughput are one of the fundamental prerequisites. In addition these light sources must support a very high NA imaging lens of more than 0.8 which determines the output spectrum of the laser to be less than 0.30 pm FWHM. In this paper we report on our recent progress in the development of high repetition rate ultra-narrow band lasers for high NA 193nm microlithography scanners. The laser, NovaLine A4003, is based on a Single Oscillator Ultral Line-narrowed (SOUL) design which yields a bandwidth of less than 0.30pm FWHM. The SOUL laser enables superior optical performance without adding complexity or cost up to the 4 kHz maximum repetition rate. The A4003's high precision line-narrowing optics used in combination with the high repetition rate of 4 kHz yields an output power of 20 W at an extremely narrow spectral bandwidth of less than 0.30 pm FWHM and highest spectral purity of less than 0.75 pm for the 95% energy content. We present performance and reliability data and discuss the key laser parameters. Improvements in the laser-internal metrology and faster regulation control result in better energy stability and improved overall operation behavior. The design considerations for line narrowing and stable laser operation at high repetition rates are discussed.

  8. A tunable, single frequency, fiber ring at 1053 nm

    SciTech Connect

    Wilcox, R.B.

    1997-02-21

    This laser is a tunable source designed for applications where a shorter pulse will be chopped from a long Q-switched pulse by electrooptic modulators, then amplified in Nd:phosphate glass. The laser employs ytterbium-doped silica fiber as the gain medium, pumped by a laser diode at 980nm. Gain in Yb:silica is distributed over an 90nm range, making it suitable for operation at many wavelengths. Our previous experiments with this medium demonstrated oscillation over a 50nm wide band. In addition, pumping at 980nm allows the use of stable pump diodes used in erbium-doped fiber amplifiers (EDFA`s). We designed the laser to take advantage of this wideband gain medium, and yet operate on a single cavity mode. A circulator causes unidirectional operation, and allows use of a fiber grating in reflection. This grating has a 0.2 Angstrom bandwidth, and defines the coarse tuning of the laser. It is piezoelectrically stretch tuned to the desired wavelength band. A single mode of the cavity is selected by a piezoelectrically tuned fiber grating Fabry-Perot etalon with 64MHz bandwidth. The laser is Q-switched by a bulk acousto-optic device at lkhz reprate. The loss is controlled to allow the oscillator to lase close to threshold for 500{micro}s before the Q-switch is turned off completely, creating a pulse. This ``pre-lasing`` stabilizes the single mode, since Q-switch pulse builds up from the prelase level. To prevent mode hopping during long term operation, cavity length is feedback controlled. Another piezoelectric device stretches a fiber in the cavity according to an error signal derived from the output optical signal. Due to the long, high loss cavity, the Q-switched pulse is about 3OOns long. The central part of this pulse will be gated by an electrooptic modulator to produce a 30ns square pulse, used for further amplification and modulation.

  9. MoSi absorber photomask for 32nm node

    NASA Astrophysics Data System (ADS)

    Konishi, Toshio; Kojima, Yosuke; Takahashi, Hiroyuki; Tanabe, Masato; Haraguchi, Takashi; Lamantia, Matthew; Fukushima, Yuichi; Okuda, Yoshimitsu

    2008-05-01

    The development of semiconductor process for 32nm node is in progress. Immersion lithography has been introduced as an extension of 193nm lithograpy. In addition, DPL (Double patterning lithography) is becoming a strong candidate of next generation lithography. The extension of optical lithography increases more mask complexity and tighter specification of photomasks. CD performance is the most important issue in the advanced photomask technology. However, it is expected that conventional mask cannot satisfy the required mask specifications for 32nm node and beyond. Most of CD errors are contributed to the dry etching process. Mask CD variation is greatly influenced by the loading effect from dry etching of the absorber. As the required accuracy of the mask arises, Cr absorber thickness has been gradually thinner. CD linearity with the thinner Cr absorber thickness has better performance. However, it is difficult to apply thinner Cr absorber thickness simply under the condition of OD > 3, which is needed for wafer printing. So, we adopted MoSi absorber instead of conventional Cr absorber, because MoSi absorber has less micro and global loading effect than that of Cr absorber. By using MoSi absorber, we can reduce Cr thickness as a hardmask. The thinner Cr hardmask allows for reduce resist thickness and become same condition for conventional EB resist lithography. The lithography performances were confirmed by the simulation and wafer printing. The new MoSi absorber mask behaves similar to the conventional Cr absorber mask. The adoption of super thin Cr as a hardmask made it possible to reduce resist thickness. By the application of the thin resist and the latest tools, we'll improve the mask performance to meet the 32 nm generation specification.

  10. Quasi-cw 808-nm 300-W laser diode arrays

    NASA Astrophysics Data System (ADS)

    Bezotosnyi, V. V.; Kozyrev, A. A.; Kondakova, N. S.; Kondakov, S. A.; Krokhin, O. N.; Mikaelyan, G. T.; Oleshchenko, V. A.; Popov, Yu. M.; Cheshev, E. A.

    2017-02-01

    Samples of 808-nm quasi-cw laser diode arrays (LDAs) with an output power exceeding 300 W, a pulse duration of 200 μs, and a pulse repetition rate of 100 Hz are developed and fabricated. The main output parameters of a set of five LDAs, including light – current characteristics, current – voltage characteristics, and emission spectra are measured. Preliminary life tests show that the LDA power remains stable for 108 pulses.

  11. Electromechanical imaging of biological systems with sub-10 nm resolution

    NASA Astrophysics Data System (ADS)

    Kalinin, Sergei V.; Rodriguez, B. J.; Jesse, S.; Thundat, T.; Gruverman, A.

    2005-08-01

    Electromechanical imaging of tooth dentin and enamel has been performed with sub-10nm resolution using piezoresponse force microscopy. Characteristic piezoelectric domain size and local protein fiber ordering in dentin have been determined. The shape of a single protein fibril in enamel is visualized in real space and local hysteresis loops are measured. Because of the ubiquitous presence of piezoelectricity in biological systems, this approach is expected to find broad application in high-resolution studies of a wide range of biomaterials.

  12. Hard x-ray Zernike microscopy reaches 30 nm resolution.

    SciTech Connect

    Chen, Y.; Chen, T.; Yi, J.; Chu, Y.; Lee, W.-K.; Wang, C.; Kempson, I.; Hwu, Y.; Gajdosik, V.; Margaritondo, G.

    2011-03-30

    Since its invention in 1930, Zernike phase contrast has been a pillar in optical microscopy and more recently in x-ray microscopy, in particular for low-absorption-contrast biological specimens. We experimentally demonstrate that hard-x-ray Zernike microscopy now reaches a lateral resolution below 30?nm while strongly enhancing the contrast, thus opening many new research opportunities in biomedicine and materials science.

  13. Hard x-ray Zernike Microscopy Reaches 30 nm Resolution

    SciTech Connect

    Chen, Y.T.; Chu, Y.; Chen, T-Y.; Yi, J.; Lee, W-K.; Wang, C-L.; Kempson, I. M.; Hwu, Y.; Gajdosik, V.; Margaritondo, G.

    2011-03-30

    Since its invention in 1930, Zernike phase contrast has been a pillar in optical microscopy and more recently in x-ray microscopy, in particular for low-absorption-contrast biological specimens. We experimentally demonstrate that hard-x-ray Zernike microscopy now reaches a lateral resolution below 30 nm while strongly enhancing the contrast, thus opening many new research opportunities in biomedicine and materials science.

  14. The polarization properties of Fe II 614.9 nm

    NASA Technical Reports Server (NTRS)

    Lites, Bruce W.

    1993-01-01

    The anomalous Zeeman splitting of the Fe II line at 614.9 nm results in four unusual properties of the polarization signature of this line in the presence of magnetic fields: the absence of linear polarization, no magnetooptical effect, the independence of intensity at line center from the inclination of the field, and a depolarizing self-absorption. The origin of these properties is illustrated in terms of the transfer of line radiation in an idealized solar atmosphere.

  15. Photodissociation cross section of ClOOCl at 330 nm.

    PubMed

    Jin, Bing; Chen, I-Cheng; Huang, Wen-Tsung; Lien, Chien-Yu; Guchhait, Nikhil; Lin, Jim J

    2010-04-15

    The photolysis rate of ClOOCl is crucial in the catalytic destruction of polar stratospheric ozone. In this work, we determined the photodissociation cross section of ClOOCl at 330 nm with a molecular beam and with mass-resolved detection. The photodissociation cross section is the product of the absorption cross section and the dissociation quantum yield. We formed an effusive molecular beam of ClOOCl at a nozzle temperature of 200 or 250 K and determined its photodissociation probability by measuring the decrease of the ClOOCl intensity upon laser irradiation. By comparing with a reference molecule (Cl(2)), of which the absorption cross section and dissociation quantum yield are well-known, we determined the absolute photodissociation cross section of ClOOCl at 330 nm to be (2.31 +/- 0.11) x 10(-19) cm(2) at 200 K and (2.47 +/- 0.12) x 10(-19) cm(2) at 250 K. Impurity interference has been a well-recognized problem in conventional spectroscopic studies of ClOOCl; our mass-resolved measurement directly overcomes such a problem. This measurement of the ClOOCl photolysis cross section at 330 nm is particularly useful in constraining its atmospheric photolysis rate, which in the polar stratosphere peaks near this wavelength.

  16. Brain lesion induced by 1319nm laser radiation

    NASA Astrophysics Data System (ADS)

    Yang, Zaifu; Chen, Hongxia; Wang, Jiarui; Chen, Peng; Ma, Ping; Qian, Huanwen

    2010-11-01

    The laser-tissue interaction has not been well defined at the 1319 nm wavelength for brain exposure. The goal of this research effort was to identify the behavioral and histological changes of brain lesion induced by 1319 nm laser. The experiment was performed on China Kunming mice. Unilateral brain lesions were created with a continuous-wave Nd:YAG laser (1319nm). The brain lesions were identified through behavioral observation and histological haematoxylin and eosin (H&E) staining method. The behavior change was observed for a radiant exposure range of 97~773 J/cm2. The histology of the recovery process was identified for radiant exposure of 580 J/cm2. Subjects were sacrificed 1 hour, 1 week, 2 weeks, 3 months, 7 months and 13 months after laser irradiation. Results showed that after laser exposure, behavioral deficits, including kyphosis, tail entasia, or whole body paralysis could be noted right after the animals recovered from anesthesia while gradually disappeared within several days and never recurred again. Histologically, the laser lesion showed a typical architecture dependent on the interval following laser treatment. The central zone of coagulation necrosis is not apparent right after exposure but becomes obvious within several days. The nerotic tissue though may persist for a long time, will finally be completely resorbed. No carbonization granules formed under our exposure condition.

  17. Thin hardmask patterning stacks for the 22-nm node

    NASA Astrophysics Data System (ADS)

    Zhu, Zhimin; Piscani, Emil; Wang, Yubao; Macie, Jan; Neef, Charles J.; Smith, Brian

    2009-03-01

    This paper presents robust trilayer lithography technology for cutting-edge IC fabrication and double-patterning applications. The goal is to reduce the thickness of a silicon hardmask so that the minimum thickness of the photoresist is not limited by the etch budget and can be optimized for lithography performance. Successful results of pattern etching through a 300-nm carbon layer are presented to prove that a 13.5-nm silicon hardmask is thick enough to transfer the line pattern. Another highlight of this work is the use of a simulation tool to design the stack so that UV light is concentrated at the bottom of the trenches. This design helps to clear the resist in the trenches and prevent resist top loss. An experiment was designed to validate the assumption with 45-nm dense lines at various exposure doses, using an Exitech MS-193i immersion microstepper (NA = 1.3) at the SEMATECH Resist Test Center. Results show that such a stack design obtains very wide CD processing window and is robust for 1:3 line patterning at the diffraction limit, as well as for patterning small contact holes.

  18. 7-nm e-beam resist sensitivity characterization

    NASA Astrophysics Data System (ADS)

    Zweber, Amy; Toda, Yusuke; Sakamoto, Yoshifumi; Faure, Thomas; Rankin, Jed; Nash, Steven; Kagawa, Masayuki; Fahrenkopf, Michael; Isogawa, Takeshi; Wistrom, Richard

    2016-10-01

    Over time mask makers have been driven to low sensitivity e-beam resist materials to meet lithographic patterning needs. For 7-nm logic node, resolution enhancement techniques continue to evolve bringing more complexity on mask and additional mask builds per layer. As demonstrated in literature, low sensitivity materials are needed for low line edge roughness (LER) but impact write tool through put. In characterizing resist sensitivity for 7-nm, we explore more broadly what advantages and disadvantages moving to lower sensitivity resist materials brings, where LER, critical dimension uniformity, resolution, fogging, image placement, and write time results and trends are presented. In this paper, resist material performance are reported for sensitivities ranging from 20 to 130 μC/cm2 at 50% proximity effect correction, where the exposure will be using a single beam platform. Materials examined include negative tone resist types with chemical amplification and positive tone without chemical amplification focusing on overall trends for 7-nm e-beam resist performance.

  19. Characterization of 32nm node BEOL grating structures using scatterometry

    NASA Astrophysics Data System (ADS)

    Zangooie, Shahin; Sendelbach, Matthew; Angyal, Matthew; Archie, Charles; Vaid, Alok; Matthew, Itty; Herrera, Pedro

    2008-03-01

    Implementations of scatterometry in the back end of the line (BEOL) of the devices requires design of advanced measurement targets with attention to CMP ground rule constraints as well as model simplicity details. In this paper we outline basic design rules for scatterometry back end targets by stacking and staggering measurement pads to reduce metal pattern density in the horizontal plane of the device and to avoid progressive dishing problems along the vertical direction. Furthermore, important characteristics of the copper shapes in terms of their opaqueness and uniformity are discussed. It is shown that the M1 copper thicknesses larger than 100 nm are more than sufficient for accurate back end scatterometry implementations eliminating the need for modeling of contributions from the buried layers. AFM and ellipsometry line scans also show that the copper pads are sufficiently uniform with a sweet spot area of around 20 μm. Hence, accurate scatterometry can be done with negligible edge and/or dishing contributions if the measurement spot is placed any where within the sweet spot area. Reference metrology utilizing CD-SEM and CD-AFM techniques prove accuracy of the optical solutions for the develop inspect and final inspect grating structures. The total measurement uncertainty (TMU) values for the process of record line width are of the order of 0.77 nm and 0.35 nm at the develop inspect and final inspect levels, respectively.

  20. The analysis of polarization characteristics on 40nm memory devices

    NASA Astrophysics Data System (ADS)

    Yoo, Minae; Park, Chanha; You, Taejun; Yang, Hyunjo; Min, Young-Hong; Park, Ki-Yeop; Yim, Donggyu; Park, Sungki

    2009-03-01

    Hyper NA system has been introduced to develop sub-60nm node memory devices. Especially memory industries including DRAM and NAND Flash business have driven much finer technology to improve productivity. Polarization at hyper NA has been well known as important optical technology to enhance imaging performance and also achieve very low k1 process. The source polarization on dense structure has been used as one of the major RET techniques. The process capabilities of various layers under specific illumination and polarization have been explored. In this study, polarization characteristic on 40nm memory device will be analyzed. Especially, TE (Transverse Electric) polarization and linear X-Y polarization on hyper NA ArF system will be compared and investigated. First, IPS (Intensity in Preferred State) value will be measured with PMM (Polarization Metrology Module) to confirm polarization characteristic of each machine before simulation. Next simulation will be done to estimate the CD variation impact of each polarization to different illumination. Third, various line and space pattern of DRAM and Flash device will be analyzed under different polarized condition to see the effect of polarization on CD of actual wafer. Finally, conclusion will be made for this experiment and future work will be discussed. In this paper, the behavior of 40nm node memory devices with two types of polarization is presented and the guidelines for polarization control is discussed based on the patterning performances.

  1. Auditory nerve impulses induced by 980 nm laser.

    PubMed

    Guan, Tian; Zhu, Kai; Chen, Fei; He, Yonghong; Wang, Jian; Wu, Mocun; Nie, Guohui

    2015-08-01

    The discovery that a pulsed laser could trigger an auditory neural response inspired ongoing research on cochlear implants activated by optical stimulus rather than by electrical current. However, most studies to date have used visible light (532 nm) or long-wavelength near-infrared (>1840  nm ) and involved making a hole in the cochlea. This paper investigates the effect of optical parameters on the optically evoked compound action potentials (oCAPs) from the guinea pig cochlea, using a pulsed semiconductor near-infrared laser (980 nm) without making a hole in the cochlea. Synchronous trigger laser pulses were used to stimulate the cochlea, before and after deafening, upon varying the pulse duration (30–1000  μs ) and an amount of radiant energy (0–53.2  mJ/cm 2 ). oCAPs were successfully recorded after deafening. The amplitude of the oCAPs increased as the infrared radiant energy was increased at a fixed 50  μs pulse duration, and decreased with a longer pulse duration at a fixed 37.1  mJ/cm 2 radiant energy. The latency of the oCAPs shortened with increasing radiant energy at a fixed pulse duration. With a higher stimulation rate, the amplitude of the oCAPs’ amplitude decreased.

  2. 3D scanning Hall probe microscopy with 700 nm resolution

    NASA Astrophysics Data System (ADS)

    Dede, M.; Akram, R.; Oral, A.

    2016-10-01

    In this report, we present a three dimensional (3D) imaging of magnetic field vector B → (x,y,z) emanating from the magnetic material surfaces using a scanning Hall probe microscopy (3D-SHPM) down to a 700 nm spatial resolution. The Hall probe is used to measure Bz(x,y) on the specimen surface at different heights with the step size of Δz = 250 nm, as we move away from the surface in z direction, until the field decays to zero. These set of images are then used to get ∂Bz(x,y)/∂x and ∂Bz(x,y)/∂y at different z by numerical differentiation. Using the Maxwell's equations in the source free region, Bx(x,y) and By(x,y) can be calculated by integrating ∂Bz(x,y)/∂x and ∂Bz(x,y)/∂y in the z direction. Alternatively, the gradients can also be measured in the Hall gradiometer configuration directly. The operation of the 3D-SHPM is demonstrated by imaging Bx(x,y), By(x,y) and Bz(x,y) on a hard disk specimen at a 700 nm resolution, using both of these methods at 77 K. The system is capable of operating from 300 K down to 4 K range.

  3. Remote-sensing vibrometry at 1550 nm wavelength

    NASA Astrophysics Data System (ADS)

    Dräbenstedt, A.; Sauer, J.; Rembe, C.

    2012-06-01

    Laser-Doppler vibrometry (LDV) is a proven technique for vibration analysis of mechanical structures. A wavelength of 633 nm is usually employed because of the availability of the relatively inexpensive Helium-Neon laser source which has a good coherence behavior. However, coherence break-down through the beat of multiple longitudinal modes and the limited detector carrier-to-noise-ratio (CNR) at a measurement laser power of 1 mW have prevented a wide use of LDV in remote sensing applications. Such applications in civil engineering are bridges, towers or wind turbines. The lower photon energy of IR light at 1550 nm wavelength increases the CNR by a factor 2.4. This helps especially in the condition where the carrier power decreases below the FM threshold. We have designed a heterodyne interferometer which allows the shot noise limited detection at 1550 nm wavelength close to the theoretical possible CNR. We present calculations of the fundamental noise contributions in interferometric light detection for a comparison of the achievable CNR between common HeNe vibrometers and IR vibrometers. The calculations are backed by measurements that show the devices working close to the theoretical limits. The achievable noise level of the demodulated velocity signal is shown in dependence from the standoff distance. Our novel heterodyne interferometer has been transferred to the Polytec product RSV-150. An application example of this new sensor will be demonstrated.

  4. Advances in 193 nm excimer lasers for mass spectrometry applications

    NASA Astrophysics Data System (ADS)

    Delmdahl, Ralph; Esser, Hans-Gerd; Bonati, Guido

    2016-03-01

    Ongoing progress in mass analysis applications such as laser ablation inductively coupled mass spectrometry of solid samples and ultraviolet photoionization mediated sequencing of peptides and proteins is to a large extent driven by ultrashort wavelength excimer lasers at 193 nm. This paper will introduce the latest improvements achieved in the development of compact high repetition rate excimer lasers and elaborate on the impact on mass spectrometry instrumentation. Various performance and lifetime measurements obtained in a long-term endurance test over the course of 18 months will be shown and discussed in view of the laser source requirements of different mass spectrometry tasks. These sampling type applications are served by excimer lasers delivering pulsed 193 nm output of several mJ as well as fast repetition rates which are already approaching one Kilohertz. In order to open up the pathway from the laboratory to broader market industrial use, sufficient component lifetimes and long-term stable performance behavior have to be ensured. The obtained long-term results which will be presented are based on diverse 193 nm excimer laser tube improvements aiming at e.g. optimizing the gas flow dynamics and have extended the operational life the laser tube for the first time over several billion pulses even under high duty-cycle conditions.

  5. Photoelectron Emission Studies in CsBr at 257 nm

    SciTech Connect

    Maldonado, Juan R.; Liu, Zhi; Sun, Yun; Pianetta, Piero A.; Pease, Fabian W.; /Stanford U., Elect. Eng. Dept. /SLAC, SSRL

    2006-09-28

    CsBr/Cr photocathodes were found [1,2] to meet the requirements of a multi-electron beam lithography system operating with a light energy of 4.8 eV (257nm). The fact that photoemission was observed with a light energy below the reported 7.3 eV band gap for CsBr was not understood. This paper presents experimental results on the presence of intra-band gap absorption sites (IBAS) in CsBr thin film photo electron emitters, and presents a model based on IBAS to explain the observed photoelectron emission behavior at energies below band gap. A fluorescence band centered at 330 nm with a FWHM of about 0.34 eV was observed in CsBr/Cr samples under 257 nm laser illumination which can be attributed to IBAS and agrees well with previously obtained synchrotron photoelectron spectra[1] from the valence band of CsBr films.

  6. 450 nm diode laser: A new help in oral surgery

    PubMed Central

    Fornaini, Carlo; Rocca, Jean-Paul; Merigo, Elisabetta

    2016-01-01

    AIM To describe the performance of 450 nm diode laser in oral surgery procedures. METHODS The case described consisted of the removal of a lower lip fibroma through a blue diode laser (λ = 450 nm). RESULTS The efficacy of this device, even at very low power (1W, CW), allows us to obtain very high intra and postoperative comfort for the patient, even with just topical anaesthesia and without needing suture. The healing process was completed in one week and, during the follow-up, the patient did not report any problems, pain or discomfort even without the consumption of any kind of drugs, such as painkillers and antibiotics. The histological examination performed by the pathologist showed a large area of fibrous connective tissue with some portions of epithelium-connective detachments and a regular incision with very scanty areas of carbonization. CONCLUSION The 450 nm diode laser proved of being very efficient in the oral soft tissue surgical procedures, with no side effects for the patients. PMID:27672639

  7. 50 nm DNA nanoarrays generated from uniform oligonucleotide films.

    PubMed

    Noh, Hyunwoo; Hung, Albert M; Choi, Chulmin; Lee, Ju Hun; Kim, Jin-Yeol; Jin, Sungho; Cha, Jennifer N

    2009-08-25

    One of the most challenging but potentially rewarding goals in nanoscience is the ability to direct the assembly of nanoscale materials into functional architectures with high yields, minimal steps, and inexpensive procedures. Despite their unique physical properties, the inherent difficulties of engineering wafer-level arrays of useful devices from nanoscale materials in a cost-effective manner have provided serious roadblocks toward technological impact. To address nanoscale features while still maintaining low fabrication costs, we demonstrate here an inexpensive printing method that enables repeated patterning of large-area arrays of nanoscale materials. DNA strands were patterned over 4 mm areas with 50 nm resolution by a soft-lithographic subtraction printing process, and DNA hybridization was used to direct the assembly of sub-20 nm materials to create highly ordered two-dimensional nanoparticle arrays. The entire printing and assembly process was accomplished in as few as three fabrication steps and required only a single lithographically templated silicon master that could be used repeatedly. The low-cost procedures developed to generate nanoscale DNA patterns can be easily extended toward roll-to-roll assembly of nanoscale materials with sub-50 nm resolution and fidelity.

  8. 551 nm Generation by sum-frequency mixing of intracavity pumped Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Dong, Y.; Li, S. T.; Zhang, X. H.

    2012-02-01

    We present for the first time a Nd:YAG laser emitting at 1319 nm intracavity pumped by a 946 nm diode-pumped Nd:YAG laser. A 809 nm laser diode is used to pump the first Nd:YAG crystal emitting at 946 nm, and the second Nd:YAG laser emitting at 1319 nm intracavity pumped at 946 nm. Intracavity sumfrequency mixing at 946 and 1319 nm was then realized in a LBO crystal to reach the yellow range. We obtained a continuous-wave output power of 158 mW at 551 nm with a pump laser diode emitting 18.7 W at 809 nm.

  9. Photodissociation of vinyl cyanide at 193 nm: Nascent product distributions of the molecular elimination channels

    SciTech Connect

    Wilhelm, Michael J.; Nikow, Matthew; Letendre, Laura; Dai Hailung

    2009-01-28

    The photodissociation dynamics of vinyl cyanide (H{sub 2}CCHCN, acrylonitrile) and deuterated vinyl cyanide (D{sub 2}CCDCN) at 193 nm are examined using time-resolved Fourier transform infrared emission spectroscopy. Prior photofragment translational spectroscopy studies [D. A. Blank et al., J. Chem. Phys. 108, 5784 (1998)] of the dissociation have observed the presence of four main dissociation channels; two molecular and two radical in nature. However, with the exception of a<0.01 quantum yield determined for the CN radical loss channel, the branching ratios of the remaining three elimination channels were not measured. The time-resolved emission spectra, including those from the deuterated samples, revealed the presence of acetylene, hydrogen cyanide (HCN), as well as the energetically less stable isomer hydrogen isocyanide (HNC). Acetylene is found in two distinct energetic distributions, suggesting that both three- and four-centered elimination reactions are occurring significantly in the dissociation. In contrast to prior ab initio studies that have suggested the dominant nature of the three-center elimination of molecular hydrogen (H{sub 2}) and cyanovinylidene (:C=CHCN), we find this reaction channel to be of little importance as there is no evidence to support any significant presence of rovibrationally excited cyanoacetylene. Spectral modeling of the product distributions allows for the first experimental determination of the relative occurrence of the three-centered (resulting in HCN+vinylidene) versus four-centered (HNC+acetylene) elimination channels as 3.34 to 1.00, in contrast to the previously calculated value of 126:1. Rice-Ramsperger-Kassel-Marcus analysis depicts that the transition state energy of the four-centered reaction should be about 10 kcal mole{sup -1} lower than the three-centered reaction.

  10. Vortex State in Sub-100 nm Magnetic Nanodots.

    NASA Astrophysics Data System (ADS)

    Roshchin, Igor V.

    2006-03-01

    Magnetism of nanostructured magnets, which size is comparable to or smaller than ferromagnetic domain size, offers a great potential for new physics. Detailed knowledge of magnetization reversal and possible magnetic configurations in magnetic nanostructures is essential for high-density magnetic memory. Many theoretical and experimental studies are focused on a magnetic vortex which in addition to a circular in-plane configuration of spins has a core, - the region with out-of-plane magnetization. We present a quantitative study of the magnetic vortex state and the vortex core in sub-100 nm magnetic dots. Arrays of single-layer and bilayer nanodots covering over 1 cm^2 are fabricated using self-assembled nanopores in anodized alumina. This method allows good control over the dot size and periodicity. Magnetization measurements performed using SQUID, VSM, and MOKE indicate a transition from a vortex to a single domain state for the Fe dots. This transition is studied as a function of the magnetic field and dots size. Micromagnetic and Monte Carlo simulations confirm the experimental observations. Thermal activation and exchange bias strongly affect the vortex nucleation field and have a much weaker effect on the vortex annihilation field. Direct imaging of magnetic moments in sub-100 nm dots is extremely difficult and has not been reported yet. Polarized grazing incidence small angle neutron scattering measurements allow dot imaging in reciprocal space. Quantitative analysis of such measurements performed on 65 nm Fe dots yields the vortex core size of ˜15 nm, in good agreement with the 14 nm obtained from the simulations. This work is done in collaboration with Chang-Peng Li, Zhi-Pan Li, S. Roy, S. K. Sinha, (UCSD), Xavier Batlle (U. Barcelona), R. K. Dumas, Kai Liu, (UC Davis), S. Park, R. Pynn, M. R. Fitzsimmons (LANL), J. Mejia Lopez (Pontificia U. Catolica de Chile), D. Altbir, (U. de Santiago de Chile), A. H. Romero (Cinvestav-Unidad Queretaro), and Ivan K

  11. Inline detection of Chrome degradation on binary 193nm photomasks

    NASA Astrophysics Data System (ADS)

    Dufaye, Félix; Sippel, Astrid; Wylie, Mark; García-Berríos, Edgardo; Crawford, Charles; Hess, Carl; Sartelli, Luca; Pogliani, Carlo; Miyashita, Hiroyuki; Gough, Stuart; Sundermann, Frank; Brochard, Christophe

    2013-09-01

    193nm binary photomasks are still used in the semiconductor industry for the lithography of some critical layers for the nodes 90nm and 65nm, with high volumes and over long periods. However, these 193nm binary photomasks can be impacted by a phenomenon of chrome oxidation leading to critical dimensions uniformity (CDU) degradation with a pronounced radial signature. If not detected early enough, this CDU degradation may cause defectivity issues and lower yield on wafers. Fortunately, a standard cleaning and repellicle service at the mask shop has been demonstrated as efficient to remove the grown materials and get the photomask CD back on target.Some detection methods have been already described in literature, such as wafer CD intrafield monitoring (ACLV), giving reliable results but also consuming additional SEM time with less precision than direct photomask measurement. In this paper, we propose another approach, by monitoring the CDU directly on the photomask, concurrently with defect inspection for regular requalification to production for wafer fabs. For this study, we focused on a Metal layer in a 90nm technology node. Wafers have been exposed with production conditions and then measured by SEM-CD. Afterwards, this photomask has been measured with a SEM-CD in mask shop and also inspected on a KLA-Tencor X5.2 inspection system, with pixels 125 and 90nm, to evaluate the Intensity based Critical Dimension Uniformity (iCDU) option. iCDU was firstly developed to provide feed-forward CDU maps for scanner intrafield corrections, from arrayed dense structures on memory photomasks. Due to layout complexity and differing feature types, CDU monitoring on logic photomasks used to pose unique challenges.The selection of suitable feature types for CDU monitoring on logic photomasks is no longer an issue, since the transmitted intensity map gives all the needed information, as shown in this paper. In this study, the photomask was heavily degraded after more than 18,000 300

  12. KEY COMPARISON: Final report on CCPR K1-a: Spectral irradiance from 250 nm to 2500 nm

    NASA Astrophysics Data System (ADS)

    Woolliams, Emma R.; Fox, Nigel P.; Cox, Maurice G.; Harris, Peter M.; Harrison, Neil J.

    2006-01-01

    The CCPR K1-a key comparison of spectral irradiance (from 250 nm to 2500 nm) was carried out to meet the requirements of the Mutual Recognition Arrangement by 13 participating national metrology institutes (NMIs). Because of the fragile nature of the tungsten halogen lamps used as comparison artefacts, the comparison was arranged as a star comparison with three lamps per participant. NPL (United Kingdom) piloted the comparison and, by measuring all lamps, provided a link between participants' measurements. The other participants were BNM-INM (France), CENAM (Mexico), CSIRO (Australia), HUT (Finland), IFA-CSIC (Spain), MSL-IRL (New Zealand), NIM (China), NIST (United States of America), NMIJ (Japan), NRC (Canada), PTB (Germany) and VNIIOFI (Russian Federation). Before the analysis was completed and the results known, the pilot discussed with each participant which lamp measurements should be included as representative of their comparison. As a consequence of this check, at least one measurement was excluded from one third of the lamps because of changes due to transportations. The comparison thus highlighted the difficulty regarding the availability of suitable transfer standards for the dissemination of spectral irradiance. The use of multiple lamps and multiple measurements ensured sufficient redundancy that all participants were adequately represented. In addition, during this pre-draft A phase all participants had the opportunity to review the uncertainty budgets and methods of all other participants. This new process helped to ensure that all submitted results and their associated uncertainties were evaluated in a consistent manner. The comparison was analysed using a model-based method which regarded each lamp as having a stable spectral irradiance and the measurements made by an NMI as systematically influenced by a factor that applies to all that NMI's measurements. The aim of the analysis was to estimate the systematic factor for each NMI. Across the

  13. RELATIVISTIC CALCULATION OF TRANSITION PROBABILITIES FOR 557.7 nm AND 297.2 nm EMISSION LINES IN OXYGEN

    SciTech Connect

    Chantler, C. T.; Nguyen, T. V. B.; Lowe, J. A.; Grant, I. P.

    2013-05-20

    The 557.7 nm green line and the 297.2 nm ultraviolet line in oxygen have been studied extensively due to their importance in astrophysics and atmospheric science. Despite the enormous effort devoted to these two prominent transition lines over 30 years, and in fact going back to 1934, the ratio of their transition probabilities remains a subject of major discrepancies amongst various theoretical calculations for many decades. Moreover, theoretical results are inconsistent with available laboratory results, as well as recent spacecraft measurements of Earth's airglow. This work presents new relativistic theoretical calculations of the transition probabilities of these two photoemission lines from neutral oxygen using the multi-configuration Dirac-Hartree-Fock method. Our calculations were performed in both length and velocity gauges in order to check for accuracy and consistency, with agreement to 8%. Whilst remaining a challenging computation, these results directly bear upon interpretations of plasma processes and ionization regimes in the universe.

  14. Combined fractional resurfacing (10600 nm/1540 nm): Tridimensional imaging evaluation of a new device for skin rejuvenation.

    PubMed

    Mezzana, Paolo; Valeriani, Maurizio; Valeriani, Roberto

    2016-11-01

    In this study were described the results, by tridimensional imaging evaluation, of the new "Combined Fractional Resurfacing" technique with the first fractional laser that overtakes the limits of traditional ablative, nonablative fractional resurfacing by combining CO2 ablative and GaAs nonablative lasers. These two wavelengths can work separately or in a mixed modality to give the best treatment choice to all the patients. In this study, it is demonstrated that the simultaneous combination of the CO2 wavelength (10600 nm) and GaAs wavelength (1540 nm) reduced the downtime, reduced pain during the treatment, and produced better results on fine wrinkles reduction and almost the same results on pigmentation as seen with 3D analysis by Antera (Miravex).

  15. Sub-70 nm resolution tabletop microscopy at 13.8 nm using a compact laser-plasma EUV source.

    PubMed

    Wachulak, Przemyslaw W; Bartnik, Andrzej; Fiedorowicz, Henryk

    2010-07-15

    We report the first (to our knowledge) demonstration of a tabletop, extreme UV (EUV) transmission microscope at 13.8 nm wavelength with a spatial (half-pitch) resolution of 69 nm. In the experiment, a compact laser-plasma EUV source based on a gas puff target is applied to illuminate an object. A multilayer ellipsoidal mirror is used to focus quasi-monochromatic EUV radiation onto the object, while a Fresnel zone plate objective forms the image. The experiment and the spatial resolution measurements, based on a knife-edge test, are described. The results might be useful for the realization of a compact high-resolution tabletop imaging systems for actinic defect characterization.

  16. Novel 980-nm and 490-nm light sources using vertical-cavity lasers with extended coupled cavities

    NASA Astrophysics Data System (ADS)

    McInerney, John G.; Mooradian, Aram; Lewis, Alan; Shchegrov, Andrei V.; Strzelecka, Eva M.; Lee, Dicky; Watson, Jason P.; Liebman, Michael K.; Carey, Glen P.; Umbrasas, Arvydas; Amsden, Charles A.; Cantos, Brad D.; Hitchens, William R.; Heald, David L.; Doan, Vincent

    2003-06-01

    We have developed novel electrically pumped, surface-emitting lasers emitting at 980 nm with an extended coupled cavity. The concept is scalable from monolithic low power (~10 mW) devices all the way to high power extended cavity lasers. The latter have demonstrated ~1 W cw multi-mode and 0.5 W cw in a TEM00 mode and a single frequency, with 90% coupling efficiency into a single-mode fiber. By inserting a nonlinear optical medium in the external cavity, efficient and compact frequency doubling has been achieved with CW output powers 5-40 mW demonstrated at 490 nm. The latter devices are especially noteworthy due to their very low noise (0.05% rms from dc-2 MHz), sub 10 mrad beam pointing stability combined with small size, low power consumption (<10 W) and high efficiency.

  17. Megahertz FDML laser with up to 143nm sweep range for ultrahigh resolution OCT at 1050nm

    NASA Astrophysics Data System (ADS)

    Kolb, Jan Philip; Klein, Thomas; Eibl, Matthias; Pfeiffer, Tom; Wieser, Wolfgang; Huber, Robert

    2016-03-01

    We present a new design of a Fourier Domain Mode Locked laser (FDML laser), which provides a new record in sweep range at ~1μm center wavelength: At the fundamental sweep rate of 2x417 kHz we reach 143nm bandwidth and 120nm with 4x buffering at 1.67MHz sweep rate. The latter configuration of our system is characterized: The FWHM of the point spread function (PSF) of a mirror is 5.6μm (in tissue). Human in vivo retinal imaging is performed with the MHz laser showing more details in vascular structures. Here we could measure an axial resolution of 6.0μm by determining the FWHM of specular reflex in the image. Additionally, challenges related to such a high sweep bandwidth such as water absorption are investigated.

  18. Evaluation of high quantum efficiency silicon photodiodes for calibration in the 400 nm to 900 nm spectral region

    NASA Technical Reports Server (NTRS)

    Jorquera, Carlos; Bruegge, Carol; Duval, Valerie

    1992-01-01

    The reflectance and internal quantum efficiency (QE) of three single-element photodiodes are determined using two different light-trapping devices. The QED-200 light trapping device which is based on inversion layer photodiodes exhibits the best performance within the short wavelengths of the visible spectrum (VIS), while the A-O device based on p-n photodiodes, performs best in the long wave VIS up to 950 nm. The combination of the two light-traps provides nearly 100 percent external QE coverage from 400 to 950 nm. The reflectances and internal QE were determined within this spectral range for three photodiodes: UV100, an inversion layer photodiode; X-UV100, a shallow diffused n-p photodiode; and 10DPI/SB, a blue-enhanced p-n photodiode.

  19. High reliability level on single-mode 980nm-1060 nm diode lasers for telecommunication and industrial applications

    NASA Astrophysics Data System (ADS)

    Van de Casteele, J.; Bettiati, M.; Laruelle, F.; Cargemel, V.; Pagnod-Rossiaux, P.; Garabedian, P.; Raymond, L.; Laffitte, D.; Fromy, S.; Chambonnet, D.; Hirtz, J. P.

    2008-02-01

    We demonstrate very high reliability level on 980-1060nm high-power single-mode lasers through multi-cell tests. First, we show how our chip design and technology enables high reliability levels. Then, we aged 758 devices during 9500 hours among 6 cells with high current (0.8A-1.2A) and high submount temperature (65°C-105°C) for the reliability demonstration. Sudden catastrophic failure is the main degradation mechanism observed. A statistical failure rate model gives an Arrhenius thermal activation energy of 0.51eV and a power law forward current acceleration factor of 5.9. For high-power submarine applications (360mW pump module output optical power), this model exhibits a failure rate as low as 9 FIT at 13°C, while ultra-high power terrestrial modules (600mW) lie below 220 FIT at 25°C. Wear-out phenomena is observed only for very high current level without any reliability impact under 1.1A. For the 1060nm chip, step-stress tests were performed and a set of devices were aged during more than 2000 hours in different stress conditions. First results are in accordance with 980nm product with more than 100khours estimated MTTF. These reliability and performance features of 980-1060nm laser diodes will make high-power single-mode emitters the best choice for a number of telecommunication and industrial applications in the next few years.

  20. Comparison of the photothermal effects of 808nm gold nanorod and indocyanine green solutions using an 805nm diode laser

    NASA Astrophysics Data System (ADS)

    Hasanjee, Aamr M.; Zhou, Feifan; West, Connor; Silk, Kegan; Doughty, Austin; Bahavar, Cody F.; Chen, Wei R.

    2016-03-01

    Non-invasive laser immunotherapy (NLIT) is a treatment method for metastatic cancer which combines noninvasive laser irradiation with immunologically modified nanostructures to ablate a primary tumor and induce a systemic anti-tumor response. To further expand the development of NLIT, two different photosensitizing agents were compared: gold nanorods (GNR) with an optical absorption peak of 808 nm and indocyanine green (ICG) with an optical absorption peak of ~800 nm. Various concentrations of GNR and ICG solutions were irradiated at different power densities using an 805 nm diode laser, and the temperature of the solutions was monitored during irradiation using a thermal camera. For comparison, dye balls made up of a 1:1 volume ratio of gel solution to GNR or ICG solution were placed in phantom gels and were then irradiated using the 805 nm diode laser to imitate the effect of laser irradiation on in vivo tumors. Non-invasive laser irradiation of GNR solution for 2 minutes resulted in a maximum increase in temperature by 31.8 °C. Additionally, similar irradiation of GNR solution dye ball within phantom gel for 10 minutes resulted in a maximum temperature increase of 8.2 °C. Comparatively, non-invasive laser irradiation of ICG solution for 2 minutes resulted in a maximum increase in temperature by 28.0 °C. Similar irradiation of ICG solution dye ball within phantom gel for 10 minutes yielded a maximum temperature increase of only 3.4 °C. Qualitatively, these studies showed that GNR solutions are more effective photosensitizing agents than ICG solution.

  1. Probing the electronic and catalytic properties of a bimetallic surface with 3 nm resolution

    NASA Astrophysics Data System (ADS)

    Zhong, Jin-Hui; Jin, Xi; Meng, Lingyan; Wang, Xiang; Su, Hai-Sheng; Yang, Zhi-Lin; Williams, Christopher T.; Ren, Bin

    2016-11-01

    An atomic- and molecular-level understanding of heterogeneous catalysis is required to characterize the nature of active sites and improve the rational design of catalysts. Achieving this level of characterization requires techniques that can correlate catalytic performances to specific surface structures, so as to avoid averaging effects. Tip-enhanced Raman spectroscopy combines scanning probe microscopy with plasmon-enhanced Raman scattering and provides simultaneous topographical and chemical information at the nano/atomic scale from ambient to ultrahigh-vacuum and electrochemical environments. Therefore, it has been used to monitor catalytic reactions and is proposed to correlate the local structure and function of heterogeneous catalysts. Bimetallic catalysts, such as Pd-Au, show superior performance in various catalytic reactions, but it has remained challenging to correlate structure and reactivity because of their structural complexity. Here, we show that TERS can chemically and spatially probe the site-specific chemical (electronic and catalytic) and physical (plasmonic) properties of an atomically well-defined Pd(sub-monolayer)/Au(111) bimetallic model catalyst at 3 nm resolution in real space using phenyl isocyanide as a probe molecule (Fig. 1a). We observe a weakened N≡C bond and enhanced reactivity of phenyl isocyanide adsorbed at the Pd step edge compared with that at the Pd terrace. Density functional theory corroborates these observations by revealing a higher d-band electronic profile for the low-coordinated Pd step edge atoms. The 3 nm spatial resolution we demonstrate here is the result of an enhanced electric field and distinct electronic properties at the step edges.

  2. High efficient photovoltaic power converter suitable for 920nm to 970nm InGaAs laser diodes

    NASA Astrophysics Data System (ADS)

    Liu, James; Wu, Ta-Chung; Cohen, Mort; Werthen, Jan G.

    2005-09-01

    In this work, we report a highly efficient Photovoltaic Power Converter (PPC) suitable for 920 nm to 970 nm InGaAs MQW lasers for the first time. The epitaxial layers were grown by low pressure MOCVD on the semi-insulting GaAs substrate. The epi layers consist of a p-n junction of In0.12Ga0.88As and the window layer of p+ AlInGaAs. The device is made of seven or eight pie-segments of equal area series-connected by means of air-bridges. Under 500mW of 940nm laser illumination, the open-circuit voltage of the eight-segment InGaAs chip is 6.7V. The short-circuit current is 29.7mA. Its maximum delivered electrical power is 171.2mW, equal to a 34.2% overall power conversion efficiency. We also demonstrate the high temperature characteristic and stability of the device.

  3. Writing time estimation of EB mask writer EBM-9000 for hp16nm/logic11nm node generation

    NASA Astrophysics Data System (ADS)

    Kamikubo, Takashi; Takekoshi, Hidekazu; Ogasawara, Munehiro; Yamada, Hirokazu; Hattori, Kiyoshi

    2014-10-01

    The scaling of semiconductor devices is slowing down because of the difficulty in establishing their functionality at the nano-size level and also because of the limitations in fabrications, mainly the delay of EUV lithography. While multigate devices (FinFET) are currently the main driver for scalability, other types of devices, such as 3D devices, are being realized to relax the scaling of the node. In lithography, double or multiple patterning using ArF immersion scanners is still a realistic solution offered for the hp16nm node fabrication. Other lithography candidates are those called NGL (Next Generation Lithography), such as DSA (Directed-Self-Assembling) or nanoimprint. In such situations, shot count for mask making by electron beam writers will not increase. Except for some layers, it is not increasing as previously predicted. On the other hand, there is another aspect that increases writing time. The exposure dose for mask writing is getting higher to meet tighter specifications of CD uniformity, in other words, reduce LER. To satisfy these requirements, a new electron beam mask writer, EBM-9000, has been developed for hp16nm/logic11nm generation. Electron optical system, which has the immersion lens system, was evolved from EBM-8000 to achieve higher current density of 800A/cm2. In this paper, recent shot count and dose trend are discussed. Also, writing time is estimated for the requirements in EBM-9000.

  4. Generation of coherent 19- and 38-nm radiation at a free-electron laser directly seeded at 38 nm.

    PubMed

    Ackermann, S; Azima, A; Bajt, S; Bödewadt, J; Curbis, F; Dachraoui, H; Delsim-Hashemi, H; Drescher, M; Düsterer, S; Faatz, B; Felber, M; Feldhaus, J; Hass, E; Hipp, U; Honkavaara, K; Ischebeck, R; Khan, S; Laarmann, T; Lechner, C; Maltezopoulos, Th; Miltchev, V; Mittenzwey, M; Rehders, M; Rönsch-Schulenburg, J; Rossbach, J; Schlarb, H; Schreiber, S; Schroedter, L; Schulz, M; Schulz, S; Tarkeshian, R; Tischer, M; Wacker, V; Wieland, M

    2013-09-13

    Initiating the gain process in a free-electron laser (FEL) from an external highly coherent source of radiation is a promising way to improve the pulse properties such as temporal coherence and synchronization performance in time-resolved pump-probe experiments at FEL facilities, but this so-called "seeding" suffers from the lack of adequate sources at short wavelengths. We report on the first successful seeding at a wavelength as short as 38.2 nm, resulting in GW-level, coherent FEL radiation pulses at this wavelength as well as significant second harmonic emission at 19.1 nm. The external seed pulses are about 1 order of magnitude shorter compared to previous experiments allowing an ultimate time resolution for the investigation of dynamic processes enabling breakthroughs in ultrafast science with FELs. The seeding pulse is the 21st harmonic of an 800-nm, 15-fs (rms) laser pulse generated in an argon medium. Methods for finding the overlap of seed pulses with electron bunches in spatial, longitudinal, and spectral dimensions are discussed and results are presented. The experiment was conducted at FLASH, the FEL user facility at DESY in Hamburg, Germany.

  5. 2 nm continuously tunable 488nm micro-integrated diode-laser-based SHG light source for Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Braune, M.; Maiwald, M.; Sumpf, B.; Tränkle, G.

    2016-04-01

    Raman spectroscopy in the visible spectral range is of great interest due to resonant Raman effects. Nevertheless, fluorescence and ambient light can mask the weak Raman lines. Shifted excitation Raman difference spectroscopy is a demonstrated tool to overcome this drawback. To apply this method, a light source with two alternating wavelengths is necessary. The spectral distance between these two wavelengths has to be adapted to the width of the Raman signal. According to the sample under investigation the width of the Raman signal could be in the range of 3 cm-1 - 12 cm-1. In this work, a micro-integrated light source emitting at 488 nm with a continuous wavelength tuning range up to 2 nm (83 cm-1) is presented. The pump source, a DFB laser emitting at 976 nm, and a periodically poled lithium niobate (PPLN) ridge waveguide crystal is used for the second harmonic generation (SHG). Both components are mounted on a μ-Peltier-element for temperature control. Here, a common wavelength tuning of the pump wavelength and the acceptance bandwidth of the SHG crystal via temperature is achieved. With the results the light source is suitable for portable Raman and SERDS experiments with a flexible spectral distance between both excitation wavelengths for SERDS with respect to the sample under investigation.

  6. Lack of photoprotection against UVB-induced erythema by immediate pigmentation induced by 382 nm radiation

    SciTech Connect

    Black, G.; Matzinger, E.; Gange, R.W.

    1985-11-01

    Immediate pigment darkening (IPD) was induced on the backs of 11 human volunteers of skin types III and IV by exposing the skin to UVA radiation (382 nm). The minimum erythema dose (MED) of UVB radiation was also determined by exposing sites to graduated doses of 304 nm radiation. The order of exposure of distinct anatomic areas was as follow: UVB followed by IPD induction; IPD induction followed by UVB; IPD induction followed 3 h later by UVB; and UVB only. Erythema responses induced by UVB were graded by inspection 24 h later and the MEDs in the 4 areas were compared. The induction of IPD before UVB exposure caused no significant change in the MED compared to sites receiving UVB only, or receiving UVA radiation after UVB, confirming that the IPD reaction does not protect against UVB-induced erythema. There was also no evidence of photorecovery, i.e., an increase in the MED of UVB resulting from exposure to longer wavelength, UV or visible radiation following UVB exposure.

  7. Below 70-nm contact hole pattern with RELACS process on ArF resist

    NASA Astrophysics Data System (ADS)

    Terai, Mamoru; Toyoshima, Toshiyuki; Ishibashi, Takeo; Tarutani, Shinji; Takahashi, Kiyohisa; Takano, Yusuke; Tanaka, Hatsuyuki

    2003-06-01

    A chemical shrink technology, RELACS (Resolution Enhancement Lithography Assisted by Chemical Shrink), utilizes the cross linking reaction catalyzed by the acid component existing in a predefined resist pattern. This "RELACS" process is a hole shrinking procedure that includes simple coating, baking, and rinsing applied after conventional photolithography. Our target is realize of sub-70nm hole pattern formation by using new RELACS for ArF resist. At present, RELACS process is introduced to mass production of KrF lithography by using AZ R200 (Product name of Clariant) mainly. Then first of all we reported process performance of conventional RELACS material, AZ R200 with ArF resist. However AZ R200 does not show satisfactory shrinkage on ArF resist. Thereupon, we started on the development of new RELACS corresponding to ArF resist. As the result, we developed new RELACS material including Cross Linking Accelerator (CLA). It was found that CLA is able to improve reactivity of RELACS with ArF-resist. By using this new RELACS, It is Realized sub-70nm hole pattern formation with ArF-Ex lithography and It is able to Control of hole size by mixing bake (MB) temperature and additive ratio of CLA. Moreover this process was realized that thickness of shrunk hole is increased.

  8. 1.7 nm platinum nanoparticles: synthesis with glucose starch, characterization and catalysis.

    PubMed

    Engelbrekt, Christian; Sørensen, Karsten Holm; Lübcke, Teis; Zhang, Jingdong; Li, Qingfeng; Pan, Chao; Bjerrum, Niels J; Ulstrup, Jens

    2010-09-10

    Monodisperse platinum nanoparticles (PtNPs) were synthesized by a green recipe. Glucose serves as a reducing agent and starch as a stabilization agent to protect the freshly formed PtNP cores in buffered aqueous solutions. Among the ten buffers studied, 2-(N-morpholino)ethanesulfonic acid (MES), ammonium acetate and phosphate are the best media for PtNP size control and fast chemical preparation. The uniform sizes of the metal cores were determined by transmission electron microscopy (TEM) and found to be 1.8 ± 0.5, 1.7 ± 0.2 and 1.6 ± 0.5 nm in phosphate, MES and ammonium acetate buffer, respectively. The estimated total diameter of the core with a starch coating layer is 5.8-6.0 nm, based on thermogravimetric analysis (TGA). The synthesis reaction is simple, environmentally friendly, highly reproducible, and easy to scale up. The PtNPs were characterized electrochemically and show high catalytic activity for reduction of dioxygen and hydrogen peroxide as well as for oxidation of dihydrogen. The PtNPs can be transferred to carbon support materials with little demand for high specific surface area of carbon. This enables utilization of graphitized carbon blacks to prepare well-dispersed Pt/C catalysts, which exhibit significantly improved durability in the accelerated aging test under fuel cell mimicking conditions.

  9. Structural design of new alicyclic acrylate polymers with androstane moiety for 193-nm resist

    NASA Astrophysics Data System (ADS)

    Aoai, Toshiaki; Sato, Kenichiro; Kodama, Kunihiko; Kawabe, Yasumasa; Nakao, Hajime; Yagihara, Morio

    1999-06-01

    Synthesis of new alicyclic (meth)acrylate polymers containing androstane moieties, especially cholic acid derivatives, and their characteristics were investigated for 193nm single layer resists. Among the derivatives, a work of adhesion, Ohnishi and ring parameters were used as measures for the adhesion and the dry-etching resistance in this study. In the synthesis of the polymers, the use of 3- (beta) -methacryloyoxy-deoxycholic acid, which is the inverse configuration against the original 3-(alpha) -structure, was effective as a monomer, because the steric hindrance at 3- (alpha) -position degraded its polymerization ability. The polymers partially protected by acid labile groups showed a satisfactory adhesion, which was probably due to the hydrophilic hydroxyl group at the 12-position and the carboxyl group linked at the 17-position, and a good dry- etching resistance. On the lithographic imaging with these polymers, the reduction of the side reaction on the acid decomposition and also the control of the flexibility on the polymers largely affected their performance. THe adjustment of the Tg values of the polymers by the co-polymerization and the change of the polymer backbone from the methacrylate to acrylate structure performed well on imaging under 193nm exposure.

  10. Latitudinal variation of 732.0 nm dayglow emission under geomagnetic storm conditions

    NASA Astrophysics Data System (ADS)

    Singh, Vir; Dharwan, Maneesha

    2016-07-01

    A comprehensive model is developed to study 732.0 nm dayglow emission. The Solar2000 EUV (extreme ultraviolet) flux model, neutral atmosphere model (NRLMSISE-00), latest transition probabilities and updated reaction rate coefficients are incorporated in the present model. The modeled volume emission rates (VER) are compared with the measurements as provided by Atmosphere Explorer-C satellite, Dynamics Explorer-2 spacecraft and WINDII measurements. The model is found in very good agreement with the measurements. This model is used to study the effects of geomagnetic storm on the 732.0 nm dayglow emission at various latitudes in northern hemisphere. It is found that the VER decreases as the latitude increases. The decrease in VER from low to mid latitudes is due to the decrease in atomic oxygen number density with latitude. The zenith intensity at the maximum geomagnetic activity is about 15% higher than the zenith intensity before the start of the geomagnetic storm in equatorial region. However, no appreciable change in the zenith intensity is found at higher latitudes (above 50° N). Further a negative correlation is found between the volume emission rate and DST index at all latitudes.

  11. Electrical and thermal conduction in atomic layer deposition nanobridges down to 7 nm thickness.

    PubMed

    Yoneoka, Shingo; Lee, Jaeho; Liger, Matthieu; Yama, Gary; Kodama, Takashi; Gunji, Marika; Provine, J; Howe, Roger T; Goodson, Kenneth E; Kenny, Thomas W

    2012-02-08

    While the literature is rich with data for the electrical behavior of nanotransistors based on semiconductor nanowires and carbon nanotubes, few data are available for ultrascaled metal interconnects that will be demanded by these devices. Atomic layer deposition (ALD), which uses a sequence of self-limiting surface reactions to achieve high-quality nanolayers, provides an unique opportunity to study the limits of electrical and thermal conduction in metal interconnects. This work measures and interprets the electrical and thermal conductivities of free-standing platinum films of thickness 7.3, 9.8, and 12.1 nm in the temperature range from 50 to 320 K. Conductivity data for the 7.3 nm bridge are reduced by 77.8% (electrical) and 66.3% (thermal) compared to bulk values due to electron scattering at material and grain boundaries. The measurement results indicate that the contribution of phonon conduction is significant in the total thermal conductivity of the ALD films.

  12. Noncanonical reactions of flavoenzymes.

    PubMed

    Sobrado, Pablo

    2012-11-05

    Enzymes containing flavin cofactors are predominantly involved in redox reactions in numerous cellular processes where the protein environment modulates the chemical reactivity of the flavin to either transfer one or two electrons. Some flavoenzymes catalyze reactions with no net redox change. In these reactions, the protein environment modulates the reactivity of the flavin to perform novel chemistries. Recent mechanistic and structural data supporting novel flavin functionalities in reactions catalyzed by chorismate synthase, type II isopentenyl diphosphate isomerase, UDP-galactopyranose mutase, and alkyl-dihydroxyacetonephosphate synthase are presented in this review. In these enzymes, the flavin plays either a direct role in acid/base reactions or as a nucleophile or electrophile. In addition, the flavin cofactor is proposed to function as a "molecular scaffold" in the formation of UDP-galactofuranose and alkyl-dihydroxyacetonephosphate by forming a covalent adduct with reaction intermediates.

  13. Reaction spreading on graphs.

    PubMed

    Burioni, Raffaella; Chibbaro, Sergio; Vergni, Davide; Vulpiani, Angelo

    2012-11-01

    We study reaction-diffusion processes on graphs through an extension of the standard reaction-diffusion equation starting from first principles. We focus on reaction spreading, i.e., on the time evolution of the reaction product M(t). At variance with pure diffusive processes, characterized by the spectral dimension d{s}, the important quantity for reaction spreading is found to be the connectivity dimension d{l}. Numerical data, in agreement with analytical estimates based on the features of n independent random walkers on the graph, show that M(t)∼t{d{l}}. In the case of Erdös-Renyi random graphs, the reaction product is characterized by an exponential growth M(t)e{αt} with α proportional to ln(k), where (k) is the average degree of the graph.

  14. Optical characterization of 193nm amorphous carbon ARC films

    NASA Astrophysics Data System (ADS)

    Leng, Jingmin; Opsal, Jon; Pois, Heath

    2005-05-01

    In this study, the optical properties of amorphous carbon (aC) ARC films are investigated using an Opti-probe OP7341, and a metrology solution that robustly measures a broad range of process conditions is presented. We find that the aC material is consistent with uni-axial anisotropy, and that this effect may have important implications for photolithography. These results are obtained through the combination of multiple technologies in one tool: spectroscopic ellipsometry (SE); spectroscopic reflectometry or broadband (BB), with a wavelength range of 190-840 nm; single wavelength (673 nm) but multiple incident angle beam profile reflectometry (BPR) and beam profile ellipsometry (BPE), and single wavelength (633nm) absolute ellipsometry (AE). The combination of technologies at multiple angles and wavelengths provides additional optical information and sensitivity not possible with single-technology approaches. A complex wavelength dependent anisotropy model was developed for this analysis, and is compared with a real anisotropy model. The complex anisotropy model and the effective medium approximation (EMA) with two and three components were applied to a set of 12 wafer set with thickness swing aC films in the range of 500-750 Å as well as a second set of 23 pre- and post- etch wafers. The complex anisotropy model clearly has the advantage of best fit the BPR profiles along with the SE Fourier coefficients. The etch rate obtained by the complex anisotropy also showed a much narrower variation as compared with the EMA2 and EMA32 models with the real anisotropy.

  15. Jupiter's Belt-Zone Boundary (Methane filter, 732 nm)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Mosaic of a belt-zone boundary near Jupiter's equator. The images that make up the four quadrants of this mosaic were taken within a few minutes of each other and show Jupiter's appearance at 732 nanometers (nm). Sunlight at 732 nm is weakly absorbed by atmospheric methane. This absorption lowers the total amount of scattered light detected by the Galileo spacecraft while enhancing the fraction that comes from higher in Jupiter's atmosphere where less methane is present. The features of the lower ammonia cloud deck that are seen at 756 nm remain visible, but features in the higher, diffuse cloud are made more apparent.

    The bowed shape of the clouds in the center of the image is created by a combination of stretching in the eastward direction by strong winds and stretching in the north-south direction by weaker winds. The precise shape of the bow and the eastward wind speeds can be measured. The north-south wind speeds, too small to be directly measured, then can be calculated. These images may provide the first indirect measurement of Jupiter's north-south winds.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  16. 28nm node process optimization: a lithography centric view

    NASA Astrophysics Data System (ADS)

    Seltmann, Rolf

    2014-10-01

    Many experts claim that the 28nm technology node will be the most cost effective technology node forever. This results from primarily from the cost of manufacturing due to the fact that 28nm is the last true Single Patterning (SP) node. It is also affected by the dramatic increase of design costs and the limited shrink factor of the next following nodes. Thus, it is assumed that this technology still will be alive still for many years. To be cost competitive, high yields are mandatory. Meanwhile, leading edge foundries have optimized the yield of the 28nm node to such a level that that it is nearly exclusively defined by random defectivity. However, it was a long way to go to come to that level. In my talk I will concentrate on the contribution of lithography to this yield learning curve. I will choose a critical metal patterning application. I will show what was needed to optimize the process window to a level beyond the usual OPC model work that was common on previous nodes. Reducing the process (in particular focus) variability is a complementary need. It will be shown which improvements were needed in tooling, process control and design-mask-wafer interaction to remove all systematic yield detractors. Over the last couple of years new scanner platforms were introduced that were targeted for both better productivity and better parametric performance. But this was not a clear run-path. It needed some extra affords of the tool suppliers together with the Fab to bring the tool variability down to the necessary level. Another important topic to reduce variability is the interaction of wafer none-planarity and lithography optimization. Having an accurate knowledge of within die topography is essential for optimum patterning. By completing both the variability reduction work and the process window enhancement work we were able to transfer the original marginal process budget to a robust positive budget and thus ensuring high yield and low costs.

  17. Ocular safety limits for 1030nm femtosecond laser cataract surgery

    NASA Astrophysics Data System (ADS)

    Wang, Jenny; Sramek, Christopher; Paulus, Yannis M.; Lavinsky, Daniel; Schuele, Georg; Anderson, Dan; Dewey, David; Palanker, Daniel V.

    2013-03-01

    Application of femtosecond lasers to cataract surgery has added unprecedented precision and reproducibility but ocular safety limits for the procedure are not well-quantified. We present an analysis of safety during laser cataract surgery considering scanned patterns, reduced blood perfusion, and light scattering on residual bubbles formed during laser cutting. Experimental results for continuous-wave 1030 nm irradiation of the retina in rabbits are used to calibrate damage threshold temperatures and perfusion rate for our computational model of ocular heating. Using conservative estimates for each safety factor, we compute the limits of the laser settings for cataract surgery that optimize procedure speed within the limits of retinal safety.

  18. Allsky Airglow Imagery from Albuquerque, NM; TOMEX 2000

    NASA Astrophysics Data System (ADS)

    Swenson, G. R.

    2001-12-01

    Allsky imager of OH Meinel and O2 Atmospheric emission bands were observed for the TOMEX rocket campaign from Albuquerque, NM, along with the Na/wind temperature lidar. Motion analysis of imagery describes a main wave propagating from the NW but other secondary waves appear from the NE to present a quasi chaotic wave field. The main wave had a typical horizontal wavelength of a several 10s of km and a period of less than15 minutes. The instrinsic wave parameters of the high frequency waves will be presented.

  19. Investigation of electron beam stabilization of 193-nm photoresists

    NASA Astrophysics Data System (ADS)

    Kim, Myoung-Soo; Park, Jong-Woon; Kim, Hak-Joon; Jun, Bum-Jin; Gil, Myung-Goon; Kim, Bong-Ho; Ross, Matthew F.; Livesay, William R.

    2001-08-01

    193nm lithography is a promising candidate for the fabrication of microelectronic devices at the 130nm design rule and below. With smaller feature sizes, below 130nm, reduced resist thickness is essential because of the pattern collapse issues at high aspect ratios and the limited depth of focus with 193nm lithography tools. However, ArF resists have shown problems with etch selectivity, especially with the thin resist layers necessary. Additionally, pattern slimming during CD-SEM measurement, due to the nature of the resist chemistry, is an issue with feature stability after patterning. At present, many studies have been performed for improving the etch selectivity of resists and addressing line slimming issues. In this study, the electron beam stabilization process has been applied for improving the etch selectivity of resist patterns having an aspect ratio less than 3.0. The electron beam stabilization has been applied to two different ArF resist types; acrylate and cyclic-olefin- maleic-anhydride (COMA), which have been evaluated with respect to materials properties, etch selectivity, and line slimming performance as a function of electron beam dose and etch condition. Film shrinkage and the change in index of refraction were monitored as a function of stabilization condition. The chemical properties were characterized before and after electron beam stabilization using FTIR analysis. Blanket resist etch rate studies were performed as a function of stabilization condition for each resist type. Cross- sectional views of resist patterns after etch processing were also investigated to evaluate the improvement in etch resistance provided by the electron beam process. CD SEM measurements were performed to evaluate the impact of the stabilization process on the patterned features. The issue of line slimming has also been evaluated, with and without electron beam stabilization, for the different ArF resist materials considered. The results were compared with a Kr

  20. Novel high sensitivity EUV photoresist for sub-7nm node

    NASA Astrophysics Data System (ADS)

    Nagai, Tomoki; Nakagawa, Hisashi; Naruoka, Takehiko; Tagawa, Seiichi; Oshima, Akihiro; Nagahara, Seiji; Shiraishi, Gosuke; Yoshihara, Kosuke; Terashita, Yuichi; Minekawa, Yukie; Buitrago, Elizabeth; Ekinci, Yasin; Yildirim, Oktay; Meeuwissen, Marieke; Hoefnagels, Rik; Rispens, Gijsbert; Verspaget, Coen; Maas, Raymond

    2016-03-01

    Extreme ultraviolet lithography (EUVL) has been recognized as the most promising candidate for the manufacture of semiconductor devices for the 7 nm node and beyond. A key point in the successful introduction of EUV lithography in high volume manufacture (HVM) is the effective EUV dose utilization while simultaneously realizing ultra-high resolution and low line edge roughness (LER). Here we show EUV resist sensitivity improvement with the use of a photosensitized chemically amplified resist PSCARTM system. The evaluation of this new chemically amplified resist (CAR) as performed using EUV interference lithography (EUV-IL) is described and the fundamentals are discussed.

  1. Fast efficient Ca atomic resonance filter at 423 nm.

    PubMed

    Walther, F G

    1992-11-15

    An optically pumped active Ca atomic resonance filter is demonstrated, applicable to background-limited optical communications through scatter channels. In pump saturation, the filter should detect 50% of the incident 423-nm signal power with an internal photon gain of 6 and a response time of 10 micros, 2 orders of magnitude faster than a passive Ca filter. Response time of 100 micros has been demonstrated, limited by available pump power. The filter maintains the wide field of view and reduced solar background associated with atomic absorption at the Ca Fraunhofer line while permitting higher data rate communications.

  2. Megasonic cleaning strategy for sub-10nm photomasks

    NASA Astrophysics Data System (ADS)

    Hsu, Jyh-Wei; Samayoa, Martin; Dress, Peter; Dietze, Uwe; Ma, Ai-Jay; Lin, Chia-Shih; Lai, Rick; Chang, Peter; Tuo, Laurent

    2016-10-01

    One of the main challenges in photomask cleaning is balancing particle removal efficiency (PRE) with pattern damage control. To overcome this challenge, a high frequency megasonic cleaning strategy is implemented. Apart from megasonic frequency and power, photomask surface conditioning also influences cleaning performance. With improved wettability, cleanliness is enhanced while pattern damage risk is simultaneously reduced. Therefore, a particle removal process based on higher megasonic frequencies, combined with proper surface pre-treatment, provides improved cleanliness without the unintended side effects of pattern damage, thus supporting the extension of megasonic cleaning technology into 10nm half pitch (hp) device node and beyond.

  3. Spectroscopy of Pluto at six longitudes, 380-930 nm

    NASA Astrophysics Data System (ADS)

    Cruikshank, Dale P.; Pinilla-Alonso, Noemi; Lorenzi, Vania; Grundy, Will M.; Licandro, Javier; Binzel, Richard P.

    2014-11-01

    We have obtained spectra of the Pluto-Charon pair (unresolved) in the wavelength range 380-930 nm with resolution ~450 at six roughly equally spaced longitudes. The data were taken in May and June, 2014, with the 4.2-m Isaac Newton Telescope at Roque de Los Muchachos Observatory in the Canary Islands, using the ACAM (auxiliary-port camera) in spectrometer mode, and using two solar analog stars. The new spectra clearly show absorption bands of solid CH4 at 620, 728, and 850-910 nm, which were known from earlier work. The 620-nm CH4 band is intrinsically very weak, and its appearance indicates a long optical pathlength through the ice. This is especially true if it arises from CH4 dissolved in N2 ice. Earlier work (Owen et al. Science 261, 745, 1993) on the near-infrared spectrum of Pluto (1-2.5 µm) has shown that the CH4 bands are shifted to shorter wavelengths because the CH4 occurs as a solute in beta-phase crystalline N2. The optical pathlength through the N2 crystals must be on the order of several cm to produce the N2 band observed at 2.15 µm. The new spectra exhibit a pronounced red slope across the entire wavelength range; the slope is variable with longitude, and differs in a small but significant way from that measured at comparable longitudes by Grundy & Fink (Icarus 124, 329, 1996) in their 15-year study of Pluto’s spectrum (500-1000 nm). The new spectra will provide an independent means for calibrating the color filter bands on the Multispectral Visible Imaging Camera (MVIC) (Reuter et al. Space Sci. Rev. 140, 129, 2008) on the New Horizons spacecraft, which will encounter the Pluto-Charon system in mid-2015. They will also form the basis of modeling the spectrum of Pluto at different longitudes to help establish the nature of the non-ice component(s) of Pluto’s surface. It is presumed that the non-ice component is the source of the yellow-red coloration of Pluto, which is known to be variable across the surface.

  4. Spectroscopy of Pluto, 380-930 Nm at Six Longitudes

    NASA Technical Reports Server (NTRS)

    Cruikshank, D. P.; Pinilla-Alonso, N.; Lorenzi, V.; Grundy, William; Licandro, J.; Binzel, R. P.

    2014-01-01

    We have obtained spectra of the Pluto-Charon pair (unresolved) in the wavelength range 380-930 nm with resolution approx..450 at six roughly equally spaced longitudes. The data were taken in May and June, 2014, with the 4.2-m Isaac Newton Telescope at Roque de Los Muchachos Observatory in the Canary Islands, using the ACAM (auxiliary-port camera) in spectrometer mode, and using two solar analog stars. The new spectra clearly show absorption bands of solid CH4 at 620, 728, and 850-910 nm, which were known from earlier work. The 620-nm CH4 band is intrinsically very weak, and its appearance indicates a long optical path-length through the ice. This is especially true if it arises from CH4 dissolved in N2 ice. Earlier work (Owen et al. Science 261, 745, 1993) on the near-infrared spectrum of Pluto (1-2.5 microns) has shown that the CH4 bands are shifted to shorter wavelengths because the CH4 occurs as a solute in beta-phase crystalline N2. The optical path-length through the N2 crystals must be on the order of several cm to produce the N2 band observed at 2.15 microns. The new spectra exhibit a pronounced red slope across the entire wavelength range; the slope is variable with longitude, and differs in a small but significant way from that measured at comparable longitudes by Grundy & Fink (Icarus 124, 329, 1996) in their 15-year study of Pluto's spectrum (500-1000 nm). The new spectra will provide an independent means for calibrating the color filter bands on the Multispectral Visible Imaging Camera (MVIC) (Reuter et al. Space Sci. Rev. 140, 129, 2008) on the New Horizons spacecraft, which will encounter the Pluto-Charon system in mid-2015. They will also form the basis of modeling the spectrum of Pluto at different longitudes to help establish the nature of the non-ice component(s) of Pluto's surface. It is presumed that the non-ice component is the source of the yellow-red coloration of Pluto, which is known to be variable across the surface.

  5. Development of high coherence high power 193nm laser

    NASA Astrophysics Data System (ADS)

    Tanaka, Satoshi; Arakawa, Masaki; Fuchimukai, Atsushi; Sasaki, Yoichi; Onose, Takashi; Kamba, Yasuhiro; Igarashi, Hironori; Qu, Chen; Tamiya, Mitsuru; Oizumi, Hiroaki; Ito, Shinji; Kakizaki, Koji; Xuan, Hongwen; Zhao, Zhigang; Kobayashi, Yohei; Mizoguchi, Hakaru

    2016-03-01

    We have been developing a hybrid 193 nm ArF laser system that consists of a solid state seeding laser and an ArF excimer laser amplifier for power-boosting. The solid state laser consists of an Yb-fiber-solid hybrid laser system and an Er-fiber laser system as fundamentals, and one LBO and three CLBO crystals for frequency conversion. In an ArF power amplifier, the seed laser passes through the ArF gain media three times, and an average power of 110 W is obtained. As a demonstration of the potential applications of the laser, an interference exposure test is performed.

  6. Photoneutron Reactions in Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Utsunomiya, Hiroaki

    Photoneutron reactions are discussed in the context of nucleosynthesis with emphasis on a unified understanding of (γ, n) and (n, γ) reactions for heavy nuclei through the γ-ray strength function and a revisit to explosive nucleosynthesis of 9Be through the reciprocity theorem. The role of photonuclear reactions in nucleosynthesis is supplemented by the photonuclear data project (IAEA-CRP F42032) and will be strengthened in the Extreme Light Infrastructure-Nuclear Physics (ELI-NP) in the future.

  7. Nuclear reaction studies

    SciTech Connect

    Alexander, J.M.; Lacey, R.A.

    1994-11-01

    Research focused on the statistical and dynamical properties of ``hot`` nuclei formed in symmetric heavy-ion reactions. Theses included ``flow`` measurements and the mechanism for multifragment disassembly. Model calculations are being performed for the reactions C+C, Ne+Al, Ar+Sc, Kr+Nb, and Xe+La. It is planned to study {sup 40}Ar reactions from 27 to 115 MeV/nucleon. 2 figs., 41 refs.

  8. Sleeve reaction chamber system

    DOEpatents

    Northrup, M. Allen; Beeman, Barton V.; Benett, William J.; Hadley, Dean R.; Landre, Phoebe; Lehew, Stacy L.; Krulevitch, Peter A.

    2009-08-25

    A chemical reaction chamber system that combines devices such as doped polysilicon for heating, bulk silicon for convective cooling, and thermoelectric (TE) coolers to augment the heating and cooling rates of the reaction chamber or chambers. In addition the system includes non-silicon-based reaction chambers such as any high thermal conductivity material used in combination with a thermoelectric cooling mechanism (i.e., Peltier device). The heat contained in the thermally conductive part of the system can be used/reused to heat the device, thereby conserving energy and expediting the heating/cooling rates. The system combines a micromachined silicon reaction chamber, for example, with an additional module/device for augmented heating/cooling using the Peltier effect. This additional module is particularly useful in extreme environments (very hot or extremely cold) where augmented heating/cooling would be useful to speed up the thermal cycling rates. The chemical reaction chamber system has various applications for synthesis or processing of organic, inorganic, or biochemical reactions, including the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction.

  9. Lower thermospheric nitric oxide concentrations derived from WINDII observations of the green nightglow continuum at 553.1 nm

    NASA Astrophysics Data System (ADS)

    von Savigny, C. H. A.; McDade, I. C.; Shepherd, G. G.; Rochon, Y.

    1999-11-01

    Vertical profiles of nitric oxide in the altitude range 90 to 105 km are derived from 553 nm nightglow continuum measurements made with the Wind Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite (UARS). The profiles are derived under the assumption that the continuum emission is due entirely to the NO+O air afterglow reaction. Vertical profiles of the atomic oxygen density, which are required to determine the nitric oxide concentrations, are derived from coordinated WINDII measurements of the atomic oxygen OI 557.7 nm nightglow emission. Data coverage for local solar times ranging from 20 h to 04 h, and latitudes ranging from 42°S to 42°N, is achieved by zonally averaging and binning data obtained on 18 nights during a two-month period extending from mid-November 1992 until mid-January 1993. The derived nitric oxide concentrations are significantly smaller than those obtained from rocket measurements of the airglow continuum but they do compare well with model expectations and nitric oxide densities measured using the resonance fluorescence technique on the Solar Mesosphere Explorer satellite. The near-global coverage of the WINDII observations and the similarities to the nitric oxide global morphology established from other satellite measurements strongly suggests that the NO+O reaction is the major source of the continuum near 553 nm and that there is no compelling reason to invoke additional sources of continuum emission in this immediate spectral region.

  10. [High-order derivative spectroscopy of infrared absorption spectra of the reaction centers from Rhodobacter sphaeroides].

    PubMed

    2005-01-01

    The infrared absorption spectra of reduced and chemically oxidized reaction center preparations from the purple bacterium Rhodobacter sphaeroides were investigated by means of high-order derivative spectroscopy. The model Gaussian band with a maximum at 810 nm and a half-band of 15 nm found in the absorption spectrum of the reduced reaction center preparation is eliminated after the oxidation of photoactive bacteriochlorophyll dimer (P). This band was related to the absorption of the P(+)y excitonic band of P. On the basis of experimental results, it was concluded that the bleaching of the P(+)y absorption band at 810 nm in the oxidized reaction center preparations gives the main contribution to the blue shift of the 800 nm absorption band of Rb. sphaeroides reaction centers.

  11. Quality metric for accurate overlay control in <20nm nodes

    NASA Astrophysics Data System (ADS)

    Klein, Dana; Amit, Eran; Cohen, Guy; Amir, Nuriel; Har-Zvi, Michael; Huang, Chin-Chou Kevin; Karur-Shanmugam, Ramkumar; Pierson, Bill; Kato, Cindy; Kurita, Hiroyuki

    2013-04-01

    The semiconductor industry is moving toward 20nm nodes and below. As the Overlay (OVL) budget is getting tighter at these advanced nodes, the importance in the accuracy in each nanometer of OVL error is critical. When process owners select OVL targets and methods for their process, they must do it wisely; otherwise the reported OVL could be inaccurate, resulting in yield loss. The same problem can occur when the target sampling map is chosen incorrectly, consisting of asymmetric targets that will cause biased correctable terms and a corrupted wafer. Total measurement uncertainty (TMU) is the main parameter that process owners use when choosing an OVL target per layer. Going towards the 20nm nodes and below, TMU will not be enough for accurate OVL control. KLA-Tencor has introduced a quality score named `Qmerit' for its imaging based OVL (IBO) targets, which is obtained on the-fly for each OVL measurement point in X & Y. This Qmerit score will enable the process owners to select compatible targets which provide accurate OVL values for their process and thereby improve their yield. Together with K-T Analyzer's ability to detect the symmetric targets across the wafer and within the field, the Archer tools will continue to provide an independent, reliable measurement of OVL error into the next advanced nodes, enabling fabs to manufacture devices that meet their tight OVL error budgets.

  12. Electrical properties of sub-100 nm SiGe nanowires

    NASA Astrophysics Data System (ADS)

    Hamawandi, B.; Noroozi, M.; Jayakumar, G.; Ergül, A.; Zahmatkesh, K.; Toprak, M. S.; Radamson, H. H.

    2016-10-01

    In this study, the electrical properties of SiGe nanowires in terms of process and fabrication integrity, measurement reliability, width scaling, and doping levels were investigated. Nanowires were fabricated on SiGe-on oxide (SGOI) wafers with thickness of 52 nm and Ge content of 47%. The first group of SiGe wires was initially formed by using conventional I-line lithography and then their size was longitudinally reduced by cutting with a focused ion beam (FIB) to any desired nanometer range down to 60 nm. The other nanowire group was manufactured directly to a chosen nanometer level by using sidewall transfer lithography (STL). It has been shown that the FIB fabrication process allows manipulation of the line width and doping level of nanowires using Ga atoms. The resistance of wires thinned by FIB was 10 times lower than STL wires which shows the possible dependency of electrical behavior on fabrication method. Project support by the Swedish Foundation for Strategic Research “SSF” (No. EM-011-0002) and the Scientific and Technological Research Council of Turkey (No. TÜBİTAK).

  13. Customized illumination shapes for 193nm immersion lithography

    NASA Astrophysics Data System (ADS)

    Ling, Moh Lung; Chua, Gek Soon; Lin, Qunying; Tay, Cho Jui; Quan, Chenggen

    2008-03-01

    In this paper, a study on customized illumination shape configurations as resolution enhancement for 45nm technology node will be presented. Several new source shape configurations will be explored through simulation based on 193nm immersion lithography on 6% Attenuated Phase Shift Mask. Forbidden pitch effect is commonly encountered in the application of off axis illumination (OAI). The illumination settings are often optimized to allow maximum process window for a pitch. This is done by creating symmetrical distribution of diffraction order on the pupil plane. However, at other pitch, the distribution of diffraction order on the pupil plane results in severe degradation in image contrast and results in significant critical dimension (CD) fluctuation. The problematic pitch is often known as forbidden pitch. It has to be avoided in the design and thus limited the pitch range to be imaged for particular illumination. An approach to modify off axis illumination to minimize the effect of forbidden pitch is explored in this study. The new customized shape for one dimensional line and space pattern is modified from current off axis illumination. Simulation study is done to evaluate the performance some customized shapes. The extent of CD fluctuation and CD through pitch uniformity is analyzed to determine the performance enhancement of the new illumination shapes. From simulation result, the proposed modification have significantly improved the through pitch performance and minimized the effect of forbidden pitch.

  14. 946 nm Diode Pumped Laser Produces 100mJ

    NASA Technical Reports Server (NTRS)

    Axenson, Theresa J.; Barnes, Norman P.; Reichle, Donald J., Jr.

    2000-01-01

    An innovative approach to obtaining high energy at 946 nm has yielded 101 mJ of laser energy with an optical-to-optical slope efficiency of 24.5%. A single gain module resonator was evaluated, yielding a maximum output energy of 50 mJ. In order to obtain higher energy a second gain module was incorporated into the resonator. This innovative approach produced un-surprised output energy of 101 mJ. This is of utmost importance since it demonstrates that the laser output energy scales directly with the number of gain modules. Therefore, higher energies can be realized by simply increasing the number of gain modules within the laser oscillator. The laser resonator incorporates two gain modules into a folded "M-shaped" resonator, allowing a quadruple pass gain within each rod. Each of these modules consists of a diode (stack of 30 microlensed 100 Watt diode array bars, each with its own fiber lens) end-pumping a Nd:YAG laser rod. The diode output is collected by a lens duct, which focuses the energy into a 2 mm diameter flat to flat octagonal pump area of the laser crystal. Special coatings have been developed to mitigate energy storage problems, including parasitic lasing and amplified spontaneous emission (ASE), and encourage the resonator to operate at the lower gain transition at 946 nm.

  15. 1125-nm quantum dot laser for tonsil thermal therapy

    NASA Astrophysics Data System (ADS)

    McMillan, Kathleen

    2011-03-01

    Thermal therapy has the potential to provide a nonexcisional alternative to tonsillectomy. Clinical implementation requires that the lymphoid tissue of tonsils is heated homogeneously to produce an amount of primary thermal injury that corresponds to gradual postoperative tonsil shrinkage, with minimal risk of damage to underlying critical blood vessels. Optical constants are derived for tonsils from tissue components and used to calculate the depth of 1/e of irradiance. The 1125 nm wavelength is shown to correspond to both deep penetration and minimal absorption by blood. A probe for tonsil thermal therapy that comprises two opposing light emitting, temperature controlled surfaces is described. For ex vivo characterization of tonsil heating, a prototype 1125 nm diode laser is used in an experimental apparatus that splits the laser output into two components, and delivers the radiation to sapphire contact window surfaces of two temperature controlled cells arranged to irradiate human tonsil specimens from opposing directions. Temperatures are measured with thermocouple microprobes at located points within the tissue during and after irradiation. Primary thermal damage corresponding to the recorded thermal histories are calculated from Arrhenius parameters for human tonsils. Results indicate homogeneous heating to temperatures corresponding to the threshold of thermal injury and above can be achieved in advantageously short irradiation times.

  16. En-face OCT system at 1060 nm

    NASA Astrophysics Data System (ADS)

    Neagu, Liviu; Lobo Ribeiro, Antonio B.; Cucu, Radu G.; Bradu, Adrian; Ma, Lisha; Podoleanu, Adrian G.

    2008-09-01

    A highly efficient power optical coherence tomography configuration is implemented using a Multiwave Photonics broadband source centred at 1060 nm wavelength, FWHM = 50 nm and a Mach Zehnder interferometer. The interferometer contains a fibre acousto-optic modulator in each arm. One is driven at a fixed frequency of 40 MHz while the other via an RF Function Generation. In this way, the en-face OCT signal is modulated on a carrier frequency adjustable in the range 0 kHz to 1.5 MHz. A circulator is placed in the sample arm. Light retroreflected from the sample is sent via the circulator to a balanced coupler where it interferes with the reference beam. A translation stage is used in the reference arm to adjust the optical path difference in the interferometer. The result is photodetected using two InGaAs photodetectors followed by a differential amplifier in a balance detection configuration The system has been used to acquire en-face images as well as cross section optical coherence tomography images from skin and embryos based on T-scans (transversal reflectivity profiles).

  17. Photofragment Translational Spectroscopy of Propargyl Radicals at 248 nm

    SciTech Connect

    Goncher, S.J.; Moore, D.T.; Sveum, N.E.; Neumark, D.M.

    2007-12-21

    The photodissociation of propargyl radical, C{sub 3}H{sub 3}, and its perdeuterated isotopolog was investigated using photofragment translational spectroscopy. Propargyl radicals were produced by 193 nm photolysis of allene entrained in a molecular beam expansion, and then photodissociated at 248 nm. photofragment time-of-flight spectra were measured at a series of laboratory angles using electron impact ionization coupled to a mass spectrometer. Data for ion masses corresponding to C{sub 3}H{sub 2}{sup +}, C{sub 3}H{sup +}, C{sub 3}{sup +}, and the analogous deuterated species show that both H and H{sub 2} loss occur. The translational energy distributions for these processes have average values = 5.7 and 15.9 kcal/mol, respectively, and are consistent with dissociation on the ground state following internal conversion, with no exit barrier for H loss but a tight transition state for H{sub 2} loss. The translational energy distribution for H atom loss is similar to that in previous work on propargyl in which the H atom, rather than the heavy fragment, was detected. The branching ratio for H loss/H{sub 2} loss was determined to be 97.6/2.4 {+-} 1.2, in good agreement with RRKM results.

  18. Spin-on organic hardmask materials in 70nm devices

    NASA Astrophysics Data System (ADS)

    Oh, Chang-Il; Uh, Dong-Seon; Kim, Do-Hyeon; Lee, Jin-Kuk; Yun, Hui-Chan; Nam, Irina; Kim, Min-Soo; Yoon, Kyong-Ho; Hyung, Kyung-Hee; Tokareva, Nataliya; Cheon, Hwan-Sung; Kim, Jong-Seob; Chang, Tu-Won

    2007-03-01

    In ArF lithography for < 90nm L/S, amorphous carbon layer (ACL) deposition becomes inevitable process because thin ArF resist itself can not provide suitable etch selectivity to sub-layers. One of the problems of ACL hardmask is surface particles which are more problematic in mass production. Limited capacity, high cost-of-ownership, and low process efficiency also make ACL hardmask a dilemma which can not be ignored by device makers. One of the answers to these problems is using a spin-on organic hardmask material instead of ACL hardmask. Therefore, several processes including bi-layer resist process (BLR), tri-layer resist process (TLR), and multi-layer resist process (MLR) have been investigated. In this paper, we have described spin-on organic hardmask materials applicable to 70nm memory devices. Applications to tri-layer resist process (TLR) were investigated in terms of photo property, etch property and process compatibility. Based on the test results described in this paper, our spin-on hardmask materials are expected to be used in mass production.

  19. Evaluation of fluorinated dissolution inhibitors for 157-nm lithography

    NASA Astrophysics Data System (ADS)

    Hamad, Alyssandrea H.; Houlihan, Francis M.; Seger, Larry; Chang, Chun; Ober, Christopher K.

    2003-06-01

    Fluorinated diesters were synthesized and evaluated as dissolution inhibitors (DIs) for 157 nm lithography. The results of dissolution rate measurements, exposure studies, and etching experiments on blends of fluorinated polymers containing these dissolution inhibitors are reported. It was shown that the DIs effectively slow the dissolution rate of the matrix polymer, poly(hexafluorohydroxyisopropyl styrene) (PHFHIPS). Etching studies show that they enhance the plasma etch resistance of poly(methyl methacrylate) using tetrafluoromethane plasma. Addition of the best performing dissolution inhibitor, cyclohexane-1,4-dicarboxylic acid bis-(1-cyclohexyl-2,2,2-trifluoro-1-methyl-ethyl) ester) (FCDE1) to candidate 157 nm photoresist polymers, Duvcor and poly(hexafluorohydroxyisopropyl styrene)-co-poly(t-butyl methacrylate) [pPHFHIPS-co-pt-BMA], improves the imaging behavior of these polymers. Our attempts to elucidate the mechanism of dissolution inhibition for this series of compounds will be discussed. Fourier Transform Infrared (FTIR) studies in conjunction with dissolution rate measurements performed on a series of DI analogues suggest a mechanism based on hydrogen bonding.

  20. High index fluoride materials for 193nm immersion lithography

    NASA Astrophysics Data System (ADS)

    Nawata, T.; Inui, Y.; Masada, I.; Nishijima, E.; Satoh, H.; Fukuda, T.

    2006-03-01

    We tried to investigate various kinds of metal fluoride materials which have higher gravity than CaF II and cubic crystal system, and we found out barium lithium fluoride (BaLiF 3) and potassium yttrium fluoride (KY 3F 10) as candidates for the last lens material. We have developed unique Czochralski (CZ) machines and techniques for the growth of large calcium fluoride single crystals. And we applied these technologies to the growth of fluoride high index materials. We have succeeded to grow the large BaLiF 3 single crystal with 120mm in diameter and a KY 3F 10 single crystal, and measured their basic properties such as refractive index, VUV transmittance, birefringence, and so on. As a result of our basic research, we found out that BaLiF 3 single crystal is transparent at VUV region, and the refractive index at 193nm is 1.64, and KY 3F 10 single crystal has the index of 1.59 at the wavelength of 193nm which is slightly higher than fused silica. We expect that these fluoride high index materials are useful for the last lens material of the next generation immersion lithography.

  1. Pressure Broadening of the Cadmium 326.1 nm Line

    NASA Astrophysics Data System (ADS)

    Roston, G. D.; Helmi, M. S.

    2014-11-01

    The temperature dependence of the Cd line absorption profile at 326.1nm perturbed by inert gases (Xe, Kr, Ar, Ne and He) has been carefully studied over a wide spectral range in both blue and red wings using a high-resolution double-beam spectrometer. The atomic densities of inert gases (Ngas) and cadmium (NCd) was sufficient to study the wing of the Cd line at 326.1nm. The temperature dependence of the studied line profile was analyzed in the framework of the quasi-static theory. The van der Waals coefficient differences (ΔC60 and ΔC61) between the ground X0+ state and the two excited states A30+ and B31 were obtained from the near red wing profile using Kuhn's law. All the results of the well depths with their positions for the ground (X0+), and the excited (31, 30+) were determined. The obtained results are compared with the corresponding theoretical and experimental molecular beam experiments results.

  2. Solid sampling with 193-nm excimer laser ablation

    NASA Astrophysics Data System (ADS)

    Delmdahl, Ralph

    2007-02-01

    Reproducible and sensitive elemental analysis of solid samples is a crucial task in areas of geology (e.g. microanalysis of fluid inclusions), material sciences, industrial quality control as well as in environmental, forensic and biological studies. To date the most versatile detection method is mass-spectroscopic multi-element analysis. In order to obtain reproducible results, this requires transferring the solid sample into the gas-phase while preserving the sample's stoichiometric composition. Laser ablation in combination with Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) is a proven powerful technique to meet the requirements for reliable solid sample analysis. The sample is laser ablated in an air-tight cell and the aerosol is carried by an inert gas to a micro-wave induced plasma where its constituents are atomized and ionized prior to mass analysis. The 193 nm excimer laser ablation, in particular, provides athermal sample ablation with very precise lateral ablation and controlled depth profiling. The high photon energy and beam homogeneity of the 193 nm excimer laser system avoids elemental fractionation and permits clean ablation of even transmissive solid materials such as carbonates, fluorites and pure quartz.

  3. Unknown Bands Observed in the 266 NM Photolysis of Iodomethanes

    NASA Astrophysics Data System (ADS)

    Du, Jia-Jen; Chen, Chia-Hsin; Chang, Bor-Chen

    2012-06-01

    Unknown bands that were not seen in the nascent emission spectra following the near-UV photolysis of bromomathanes (CHBr3-nCl_n, n= 0, 1, 2 and CH_2Br_2) were observed in the 520-820 nm region of the nascent emission spectra following the 266 nm photolysis of iodomethanes (CHI_3, CH_2I_2, and CH_3I) in a slow flow system at ambient temperature. We have dramatically improved the signal-to-noise (S/N) ratios of these unknown bands for further data analyses. Pressure dependence and temporal waveforms of the unknown bands were also recorded. The analyses show that these bands have the vibrational intervals of roughly 400 cm-1 and possibly originate from the same upper level with emission to different lower levels. Moreover, the nascent emission spectra of photolyzing the deuterated or 13C-substituted isotopomers (CD_2I_2, CD_3I, and 13CH_2I_2) were also acquired, and the results indicate that the carrier molecule probably does not contain any hydrogen or carbon atoms. Our current progress will be presented. S.-X. Yang, G.-Y. Hou, J.-H. Dai, C-.H. Chang, and B.-C. Chang, J. Phys. Chem. A 114, 4785 (2010) C.-N. Liu, H.-F. Liao, G.-Y. Hou, S-.X. Yang, and B.-C. Chang, 65 OSU International Symposium on Molecular Spectroscopy, MI10 (2010).

  4. 1060nm 28-Gbps VCSEL developed at Furukawa

    NASA Astrophysics Data System (ADS)

    Suzuki, Toshihito; Funabashi, Masaki; Shimizu, Hitoshi; Nagashima, Kazuya; Kamiya, Shinichi; Kasukawa, Akihiko

    2014-02-01

    This paper presents recent development results of our 28-Gbps VCSELs featured with double intra-cavity structure and a lasing wavelength of 1060 nm. The double intra-cavity realizes very low cavity loss due to undoped semiconductor bottom DBR and dielectric top DBR layers. Compressively strained InGaAs MQW provides high differential gain that contributes to low power consumption and high reliability. Based on our 10-Gbps VCSEL structure, we carefully optimized MQW, selective oxide structure, cavity length, and doping profile in order to achieve high speed operation while maintaining high reliability and other laser performances. The developed VCSELs exhibit modulation 3 dB-bandwidth exceeding 20 GHz and D-factor of 10 GHz/(mA)1/2. Typical threshold current and slope efficiency are 0.5 mA and 0.5 W/A, respectively. The paper also discusses static and dynamic characteristics of VCSELs with various oxide aperture sizes simultaneously fabricated on the same wafer. For a longer transmission distance and better optical coupling to a multimode fiber, optical lateral confinement is precisely controlled to reduce spectral width as well as far-field pattern. Clearly opened eye diagrams are obtained at a bit rate of 28 Gbps. Bit error rate tests are also performed and 28 Gbps error free transmission has been confirmed over 300 meters of multimode-fiber optimized for 1060 nm with a PRBS pattern length of 231-1.

  5. 1060nm VCSEL for inter-chip optical interconnection

    NASA Astrophysics Data System (ADS)

    Takaki, Keishi; Imai, Suguru; Kamiya, Shinichi; Shimizu, Hitoshi; Kawakita, Yasumasa; Hiraiwa, Koji; Takagi, Tomohiro; Shimizu, Hiroshi; Yoshida, Junji; Ishikawa, Takuya; Tsukiji, Naoki; Kasukawa, Akihiko

    2011-03-01

    The demand for the on board intra-chip optical interconnection as the "Green interconnect" have been growing so rapidly in order to catch up the speed of the performance development of high performance computing systems. In this report, our continuous study results expanding to intra-chip application in terms with power consumption and reliability are shown for the "Green" 1060nm VCSEL arrays developed by Furukawa Electric1. As the basic performance level, the clear eye opening up to 20Gbps was achieved with low power dissipation level of 160fJ/bit with voltage swing level of 130mVpp. This value would be considered as the same level of the 140fJ/bit in 10Gbps operation with 75mVpp. In the reliability test, our large scale FIT rate test had been reached up to 7.8E7 device hours and the estimated FIT rate of 30FIT/ch was obtained from no failure sample and confidence level of 90%. Our wear-out study was performed with high stress test of 170°C ambient temperature and estimated failure rate for 10years service time was 0.3FIT/ch for this mode. Our 1060nm VCSEL with low power consumption level of 140fJ/bit and high reliability of 30FIT/ch would be projected to a light source for intra-chip application.

  6. 240 nm UV LEDs for LISA test mass charge control

    NASA Astrophysics Data System (ADS)

    Olatunde, Taiwo; Shelley, Ryan; Chilton, Andrew; Serra, Paul; Ciani, Giacomo; Mueller, Guido; Conklin, John

    2015-05-01

    Test Masses inside the LISA Gravitational Reference Sensor must maintain almost pure geodesic motion for gravitational waves to be successfully detected. LISA requires residual test mass accelerations below 3 fm/s2/√Hz at all frequencies between 0.1 and 3 mHz. One of the well-known noise sources is associated with the charges on the test masses which couple to stray electrical potentials and external electromagnetic fields. LISA Pathfinder will use Hg-discharge lamps emitting mostly around 254 nm to discharge the test masses via photoemission in its 2015/16 flight. A future LISA mission launched around 2030 will likely replace the lamps with newer UV-LEDs. Presented here is a preliminary study of the effectiveness of charge control using latest generation UV-LEDs which produce light at 240 nm with energy above the work function of pure Au. Their lower mass, better power efficiency and small size make them an ideal replacement for Hg lamps.

  7. Detection of homemade explosives using Raman excitation at 1064 nm

    NASA Astrophysics Data System (ADS)

    Roy, Eric G.; Dentinger, Claire; Robotham, Claude

    2015-05-01

    Raman spectroscopy is a powerful tool for obtaining molecular structure information of a sample. While Raman spectroscopy is a common laboratory based analytical tool, miniaturization of opto-electronic components has allowed handheld Raman analyzers to become commercially available. These handheld systems are utilized by Military and Bomb squad operators tasked with rapidly identifying explosives in the field, sometimes in clandestine laboratories. However, one limitation of many handheld Raman detection systems is strong interference caused by fluorescence of the sample or underlying surface which obscures the characteristic Raman signature of the target analyte. Homemade explosives (HMEs) are produced in clandestine laboratories, and the products under these conditions are typically contaminated with degradation products, contaminants, and unreacted precursors. These contaminations often will have strong fluorescence. In this work, Raman spectra of both commercial explosives and HMEs were collected using a handheld Raman spectrometer with a 1064 nm excitation laser. While Raman scattering generated by a 1064 nm laser is inherently less efficient than excitation at shorter wavelengths, high quality spectra were easily obtained due to significantly reduced fluorescence of HMEs.

  8. 976-nm passively mode-locked ytterbium-doped fiber laser core-pumped by 915-nm semiconductor laser

    NASA Astrophysics Data System (ADS)

    Zhou, Yue

    2016-11-01

    In this paper, we demonstrate an all-normal dispersion (ANDi) femtosecond YDFL. The laser operates around 976 nm via single-clad single-mode core-pumped method, which could enhance the slope efficiency up to 19% compared to that of 14% via double-clad multi-mode pumped method. The pulse repetition rate is 44.3 MHz, and pulse energy is approximately 1 nJ. Through external cavity pulse compression by a pair of gratings, the pulse duration can be compressed to 250 fs, nearly transform-limited.

  9. Holistic overlay control for multi-patterning process layers at the 10nm and 7nm nodes

    NASA Astrophysics Data System (ADS)

    Verstappen, Leon; Mos, Evert; Wardenier, Peter; Megens, Henry; Schmitt-Weaver, Emil; Bhattacharyya, Kaustuve; Adam, Omer; Grzela, Grzegorz; van Heijst, Joost; Willems, Lotte; Wildenberg, Jochem; Ignatova, Velislava; Chen, Albert; Elich, Frank; Rajasekharan, Bijoy; Vergaij-Huizer, Lydia; Lewis, Brian; Kea, Marc; Mulkens, Jan

    2016-03-01

    Multi-patterning lithography at the 10-nm and 7-nm nodes is driving the allowed overlay error down to extreme low values. Advanced high order overlay correction schemes are needed to control the process variability. Additionally the increase of the number of split layers results in an exponential increase of metrology complexity of the total overlay and alignment tree. At the same time, the process stack includes more hard-mask steps and becomes more and more complex, with as consequence that the setup and verification of the overlay metrology recipe becomes more critical. All of the above require a holistic approach that addresses total overlay optimization from process design to process setup and control in volume manufacturing. In this paper we will present the holistic overlay control flow designed for 10-nm and 7-nm nodes and illustrate the achievable ultimate overlay performance for a logic and DRAM use case. As figure 1 illustrates we will explain the details of the steps in the holistic flow. Overlay accuracy is the driver for target design and metrology tool optimization like wavelength and polarization. We will show that it is essential to include processing effects like etching and CMP which can result in a physical asymmetry of the bottom grating of diffraction based overlay targets. We will introduce a new method to create a reference overlay map, based on metrology data using multiple wavelengths and polarization settings. A similar approach is developed for the wafer alignment step. The overlay fingerprint correction using linear or high order correction per exposure (CPE) has a large amount of parameters. It is critical to balance the metrology noise with the ultimate correction model and the related metrology sampling scheme. Similar approach is needed for the wafer align step. Both for overlay control as well as alignment we have developed methods which include efficient use of metrology time, available for an in the litho-cluster integrated

  10. Vacuum-ultraviolet (147 nm) photodecomposition of 1,1,2-trichloro-2,2-difluoroethane

    NASA Astrophysics Data System (ADS)

    Yano, T.; Tschuikow-Roux, E.

    1980-03-01

    The 147 nm photolysis of CF2ClCHCl2 has been investigated at 25 °C as a function of reactant pressure, conversion, and nitric oxide as additive. In the absence of NO the observed reaction products are CF2CHCl, CF2CCl2, and the diastereomers of (CF2ClCHCl)2. At constant reactant pressure the quantum yields of the olefin decrease with increasing conversion and there is a corresponding increase in the quantum yield of the C4 product. For fixed values of conversion the olefin quantum yields decrease with increasing reactant pressure and approach limiting values at ˜100 Torr. The addition of NO completely suppresses the formation of the chlorofluorobutanes, while it enhances the olefin quantum yields at higher conversion. These observations are interpreted in terms of reactions of chlorine atoms which result either directly (by near simultaneous expulsion of two Cl atoms), or via the dissociation of an excited Cl2* molecule produced by molecular elimination in the primary process. Chlorine atoms abstract hydrogen from the parent or add to the product olefins. These processes provide the principal source of halo-ethyl radicals in the system. The addition reaction leads to chemically activated radicals with a mean lifetime of τ?0.8×10-8 sec which is commensurate with RRKM-theory predictions. The addition of nitric oxide provides a competing channel for chlorine atom removal by way of their NO-catalyzed recombination. The functional dependence of the olefin quantum yields with conversion in the absence and presence of NO suggests that the major fraction of the principal product, CF2CHCl, derives directly from a primary process, while CF2CCl2 is formed via both, the molecular elimination of HCl and from radical precursors. The limiting quantum yields of CF2CHCl and CF2CCl2 are found to be φ0?0.68 and φ0'?0.19, in the absence of NO, respectively, and φ0,NO?0.56 and φ'0,NO?0.087 in the presence of NO. The extinction coefficient for CF2ClCHCl2 at 147 nm and 25 °C has

  11. Feasibility study of sub-10-nm-half-pitch fabrication by chemically amplified resist processes of extreme ultraviolet lithography: II. Stochastic effects

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro; Santillan, Julius Joseph; Itani, Toshiro

    2015-03-01

    Line edge roughness (LER) rapidly increases in the sub-10-nm-half-pitch region of resist processes used for the fabrication of semiconductor devices. Sub-10-nm fabrication with high throughput is a challenging task. In this study, the stochastic effects (LER and stochastic defect generation) of chemically amplified resist processes in the sub-10-nm-half-pitch node were investigated, assuming the use of extreme ultraviolet (EUV) lithography. The latent images were calculated by a Monte Carlo method on the basis of the sensitization and reaction mechanisms of chemically amplified EUV resists. 7-nm-half-pitch fabrication by chemically amplified resist processes is considered to be feasible. However, significant improvement in the efficiencies of the conversion processes from optical images to resist images is required.

  12. Ultrafast chemical reactions in shocked nitromethane probed with dynamic ellipsometry and transient absorption spectroscopy.

    PubMed

    Brown, Kathryn E; McGrane, Shawn D; Bolme, Cynthia A; Moore, David S

    2014-04-10

    Initiation of the shock driven chemical reactions and detonation of nitromethane (NM) can be sensitized by the addition of a weak base; however, the chemical mechanism by which sensitization occurs remains unclear. We investigated the shock driven chemical reaction in NM and in NM sensitized with diethylenetriamine (DETA), using a sustained 300 ps shock driven by a chirped Ti:sapphire laser. We measured the solutions' visible transient absorption spectra and measured interface particle and shock velocities of the nitromethane solutions using ultrafast dynamic ellipsometry. We found there to be a volume-increasing reaction that takes place around interface particle velocity up = 2.4 km/s and up = 2.2 km/s for neat NM and NM with 5% DETA, respectively. The rate at which transient absorption increases is similar in all mixtures, but with decreasing induction times for solutions with increasing DETA concentrations. This result supports the hypothesis that the chemical reaction mechanisms for shocked NM and NM with DETA are the same. Data from shocked NM are compared to literature experimental and theoretical data.

  13. Oscillating Reactions: Two Analogies

    ERIC Educational Resources Information Center

    Petruševski, Vladimir M.; Stojanovska, Marina I.; Šoptrajanov, Bojan T.

    2007-01-01

    Oscillating chemical reactions are truly spectacular phenomena, and demonstrations are always appreciated by the class. However, explaining such reactions to high school or first-year university students is problematic, because it may seem that no acceptable explanation is possible unless the students have profound knowledge of both physical…

  14. Degradations and Rearrangement Reactions

    NASA Astrophysics Data System (ADS)

    Zhang, Jianbo

    This section deals with recent reports concerning degradation and rearrangement reactions of free sugars as well as some glycosides. The transformations are classified in chemical and enzymatic ways. In addition, the Maillard reaction will be discussed as an example of degradation and rearrangement transformation and its application in current research in the fields of chemistry and biology.

  15. Photoinduced Multicomponent Reactions.

    PubMed

    Garbarino, Silvia; Ravelli, Davide; Protti, Stefano; Basso, Andrea

    2016-12-12

    The combination of multicomponent approaches with light-driven processes opens up new scenarios in the area of synthetic organic chemistry, where the need for sustainable, atom- and energy-efficient reactions is increasingly urgent. Photoinduced multicomponent reactions are still in their infancy, but significant developments in this area are expected in the near future.

  16. Lithium Cell Reactions.

    DTIC Science & Technology

    1983-12-01

    SUPPLEMENTARY NOTES It. KEY WORDS (Continue on reverse .,ide if necessary and Identify by block number) Batteries Thionyl Chloride Batteries Lithium ...Batteries Lithium Cells Primary Batteries Thionyl Chloride Cells Non Rechargeable Batteries Electrochemical Reactions 20. ABSTRACT (Continue on reverse...INVESTIGATION OF CHEMICAL, ELECTROCHEMICAL AND PARASITIC REACTIONS IN LITHIUM - THIONYL CHLORIDE CELLS .......................................... 1 1.0 IN TRO D UC

  17. Clock Reaction: Outreach Attraction

    ERIC Educational Resources Information Center

    Carpenter, Yuen-ying; Phillips, Heather A.; Jakubinek, Michael B.

    2010-01-01

    Chemistry students are often introduced to the concept of reaction rates through demonstrations or laboratory activities involving the well-known iodine clock reaction. For example, a laboratory experiment involving thiosulfate as an iodine scavenger is part of the first-year general chemistry laboratory curriculum at Dalhousie University. With…

  18. Hydrogen evolution reaction catalyst

    DOEpatents

    Subbaraman, Ram; Stamenkovic, Vojislav; Markovic, Nenad; Tripkovic, Dusan

    2016-02-09

    Systems and methods for a hydrogen evolution reaction catalyst are provided. Electrode material includes a plurality of clusters. The electrode exhibits bifunctionality with respect to the hydrogen evolution reaction. The electrode with clusters exhibits improved performance with respect to the intrinsic material of the electrode absent the clusters.

  19. REUSABLE REACTION VESSEL

    DOEpatents

    Soine, T.S.

    1963-02-26

    This patent shows a reusable reaction vessel for such high temperature reactions as the reduction of actinide metal chlorides by calcium metal. The vessel consists of an outer metal shell, an inner container of refractory material such as sintered magnesia, and between these, a bed of loose refractory material impregnated with thermally conductive inorganic salts. (AEC)

  20. Reactions to Attitudinal Deviancy.

    ERIC Educational Resources Information Center

    Levine, John M.; Allen, Vernon L.

    This paper presents a critical review of empirical and theoretical treatments of group reaction to attitudinal deviancy. Inspired by Festinger's (1950) ideas on resolution of attitudinal discrepancies in groups, Schachter (1951) conducted an experiment that has greatly influenced subsequent research and theory concerning reaction to attitudinal…

  1. Applications of Reaction Rate

    ERIC Educational Resources Information Center

    Cunningham, Kevin

    2007-01-01

    This article presents an assignment in which students are to research and report on a chemical reaction whose increased or decreased rate is of practical importance. Specifically, students are asked to represent the reaction they have chosen with an acceptable chemical equation, identify a factor that influences its rate and explain how and why it…

  2. Chemical Reaction Problem Solving.

    ERIC Educational Resources Information Center

    Veal, William

    1999-01-01

    Discusses the role of chemical-equation problem solving in helping students predict reaction products. Methods for helping students learn this process must be taught to students and future teachers by using pedagogical skills within the content of chemistry. Emphasizes that solving chemical reactions should involve creative cognition where…

  3. Reactions and their management.

    PubMed

    Ganapati, R; Pai, V V

    2004-12-01

    The uneventful response to chemotherapy in leprosy is marked by clinically disturbing episodes encountered in 20-30% of patients and these phenomena are called "reactions". Generally they are classified as reversal reaction (type-1) and erythema nodosum leprosum (type-2). The cutaneous menifestations are: (1) Type-2 reactions in LL, BL types constituting erythema nodosum leprosum, erythema multiforme, erythema necroticans, subcutaneous nodules, lepromatous exacerbation. (2) Type-1 reactions in borderline and tuberculoid leprosy. The other manifestations include: Acute neuritis, lymphadenitis, arthritis, oedema of the hands and feet, ocular lesions, etc. Sequelae of reactions are: Paralytic deformities, non-paralytic deformities, extensive scarring and renal damage. A simple guideline to identify the risk-prone cases has been narrated. Prednisolone in standard dosage schedule as recommended by WHO is now being widely used in control programmes.

  4. A possible candidate to be classified as an autocatalysis-driven clock reaction: kinetics of the pentathionate-iodate reaction.

    PubMed

    Xu, Li; Horváth, Attila K

    2014-08-14

    The pentathionate-iodate reaction has been investigated by spectrophotometrically monitoring the formation of the total amount of iodine at 468 nm in the presence of phosphoric acid/dihydrogen phosphate buffer. We noticed that iodine forms only after a fairly long time lag, and the inverse of time necessary to produce a certain amount of iodine is linearly proportional to the initial concentration of iodate ion and the square of the hydrogen ion concentration, while depending complexly on the concentration of substrate pentathionate. This reaction can therefore be treated as a clock reaction but differs from the original Landolt reaction in the sense that substrate pentathionate and the clock species iodine coexist for a relatively long time--due to their relatively slow direct reaction--depending on the experimental circumstances. Furthermore, we also provided experimental evidence that iodide ion acts as an autocatalyst of the system. A 14-step kinetic model is proposed in which the mechanisms of the pentathionate-iodine, bisulfite-iodate, and the well-known Dushman reactions are combined. A thorough analysis revealed that the direct pentathionate-iodate reaction plays a role only to produce iodide ions via a finite sequence of reactions, and once its concentration reaches a certain level, the reaction is almost exclusively governed by the pentathionate-iodine and the Dushman reactions. As expected, a strong catalytic effect of the buffer composition is also found that can readily be explained by its well-known catalytic influence on the original Dushman reaction.

  5. Quantum yields for the photolysis of glyoxal below 350 nm and parameterisations for its photolysis rate in the troposphere.

    PubMed

    Salter, Robert J; Blitz, Mark A; Heard, Dwayne E; Kovács, Tamás; Pilling, Michael J; Rickard, Andrew R; Seakins, Paul W

    2013-04-14

    The formation of HCO and of H in the photolysis of glyoxal have been investigated over the wavelength ranges 310-335 nm for HCO and 193-340 nm for H. Dye laser photolysis was coupled with cavity ring-down spectroscopy for HCO, and with laser induced fluorescence spectroscopy for H. Absolute quantum yields were determined using actinometers based on (a) Cl2 photolysis and the Cl + HCHO reaction for HCO and (b) N2O photolysis (and O(1)D + H2) and CH2CO photolysis (and CH2 + O2) for H. The quantum yields were found to be pressure independent in this wavelength region. Quantum yields for all product channels under atmospheric conditions were calculated and compared with literature values. Differences between this work and previously published work and their atmospheric implications are discussed.

  6. Dosimetric analysis for low-level laser therapy (LLLT) of the human inner ear at 593 nm and 633 nm

    NASA Astrophysics Data System (ADS)

    Beyer, Wolfgang; Baumgartner, Reinhold; Tauber, Stefan

    1998-12-01

    The administration of low-level-laserlight for irradiation of the inner ear could represented a new therapeutic model for complex diseases of the inner ear. However, successful therapy requires a well-defined light dosimetry based on a dosimetric analysis of the human cochlea that represents a complex anatomy. The light distribution inside the cochlear windings, produced by an irradiation of the tympanic membrane, was quantitatively measured ex vivo for HeNe laser wavelengths of 593 nm and 633 nm. To obtain the space irradiance within an intact cochlea a correction factor of about 6 has been determined by Monte Carlo calculations. It follows from 3 contributions, first the backscattering of light in the bony parts removed during the preparation procedure of the specimen, second the change of index of refraction from the bony parts to air and third some geometrical factors due to the angular distribution of the radiation. The transmission of light across the tympanic cavity and the promontory depends strongly on the wavelength. Due to the observed spatial intensity variations of a factor 10 and more inside the cochlear windings the optimum external light dose has to be chosen with regard to the tonotopy of the ear.

  7. Final report on EUROMET PR-K2.b: Comparison on spectral responsivity (300 nm to 1000 nm)

    NASA Astrophysics Data System (ADS)

    Campos, Joaquin; Pons, Alicia; Blattner, Peter; Dubard, Jimmy; Bastie, Jean; Litwiniuk, Lukasz; Pietrzykowski, Jerzy; Smid, Marek; Mihai, Sim; Bos, Daniel; Gran, Jarle; Bazkir, Ozcan; Fäldt, Anne A.

    2013-01-01

    This report contains the results of the regional comparison EUROMET PR-K2.b (registered in the KCDB under the identifier EURAMET.PR-K2.b). Ten laboratories took part in it, including the pilot. In general the results are consistent, with a few exceptions as explained in the report. The comparison gives international linkage in spectral responsivity from 300 nm to 1000 nm to seven European laboratories: Bundesamt für Metrologie und Akkreditierung (METAS), Norwegian Metrology and Accreditation Service (Justervesenet), Central Office of Measures (GUM), National Institute of Metrology (INM-Romania), Optics Laboratory of TUBITAK-UME (UME), Czech Metrology Institute (CMI) and Swedish National Testing and Research Institute (SP). Three laboratories provided the link to CCPR-K2.b: Bureau National de Metrologie (BNM-INM/CNAM), Instituto de Optica 'Daza de Valdés' (IO-CSIC, acting as pilot) and NMi Van Swinden Laboratorium BV (NMi-VSL). Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  8. Photoinitiated oxidation of geosmin and 2-methylisoborneol by irradiation with 254 nm and 185 nm UV light.

    PubMed

    Kutschera, Kristin; Börnick, Hilmar; Worch, Eckhard

    2009-05-01

    The degradation of geosmin and 2-methylisoborneol (2-MIB) by UV irradiation at different wavelengths was investigated under varying boundary conditions. The results showed that conventional UV radiation (254 nm) is ineffective in removing these compounds from water. In contrast to the usual UV radiation UV/VUV radiation (254+185 nm) was more effective in the removal of the taste and odour compounds. The degradation could be described by a simple pseudo first-order rate law with rate constants of about 1.2 x 10(-3) m(2)J(-1) for geosmin and 2-MIB in ultrapure water. In natural water used for drinking water abstraction the rate constants decreased to 2.7 x 10(-4) m(2)J(-1) for geosmin and 2.5 x 10(-4) m(2)J(-1) for 2-MIB due to the presence of NOM. Additionally, the formation of the by-product nitrite was studied. In the UV/VUV irradiation process up to 0.6 mg L(-1) nitrite was formed during the complete photoinitiated oxidation of the odour compounds. However, the addition of low ozone doses could prevent the formation of nitrite in the UV/VUV irradiation experiments.

  9. Photobiomodulation of human adipose-derived stem cells using 810nm and 980nm lasers operates via different mechanisms of action.

    PubMed

    Wang, Yuguang; Huang, Ying-Ying; Wang, Yong; Lyu, Peijun; Hamblin, Michael R

    2017-02-01

    Photobiomodulation (PBM) using red or near-infrared (NIR) light has been used to stimulate the proliferation and differentiation of adipose-derived stem cells. The use of NIR wavelengths such as 810nm is reasonably well accepted to stimulate mitochondrial activity and ATP production via absorption of photons by cytochrome c oxidase. However, the mechanism of action of 980nm is less well understood. Here we study the effects of both wavelengths (810nm and 980nm) on adipose-derived stem cells in vitro. Both wavelengths showed a biphasic dose response, but 810nm had a peak dose response at 3J/cm(2) for stimulation of proliferation at 24h, while the peak dose for 980nm was 10-100 times lower at 0.03 or 0.3J/cm(2). Moreover, 980nm (but not 810nm) increased cytosolic calcium while decreasing mitochondrial calcium. The effects of 980nm could be blocked by calcium channel blockers (capsazepine for TRPV1 and SKF96365 for TRPC channels), which had no effect on 810nm. To test the hypothesis that the chromophore for 980nm was intracellular water, which could possibly form a microscopic temperature gradient upon laser irradiation, we added cold medium (4°C) during the light exposure, or pre-incubated the cells at 42°C, both of which abrogated the effect of 980nm but not 810nm. We conclude that 980nm affects temperature-gated calcium ion channels, while 810nm largely affects mitochondrial cytochrome c oxidase.

  10. Atmospheric chemistry of hydrazoic acid (HN3): UV absorption spectrum, HO reaction rate, and reactions of the N3 radical.

    PubMed

    Orlando, John J; Tyndall, Geoffrey S; Betterton, Eric A; Lowry, Joe; Stegall, Steve T

    2005-03-15

    Processes related to the tropospheric lifetime and fate of hydrazoic acid, HN3, have been studied. The ultraviolet absorption spectrum of HN3 is shown to possess a maximum near 262 nm with a tail extending to at least 360 nm. The photolysis quantum yield for HN3 is shown to be approximately 1 at 351 nm. Using the measured spectrum and assuming unity quantum yield throughout the actinic region, a diurnally averaged photolysis lifetime near the earth's surface of 2-3 days is estimated. Using a relative rate method, the rate coefficient for reaction of HO with HN3 was found to be (3.9 +/-0.8) x 10(-12) cm3 molecule(-1) s(-1), substantially larger than the only previous measurement. The atmospheric HN3 lifetime with respect to HO oxidation is thus about 2-3 days, assuming a diurnally averaged [HO] of 10(6) molecule cm(-3). Reactions of N3, the product of the reaction of HO with HN3, were studied in an environmental chamber using an FTIR spectrometer for end-product analysis. The N3 radical reacts efficiently with NO, producing N2O with 100% yield. Reaction of N3 with NO2 appears to generate both NO and N2O, although the rate coefficient for this reaction is slower than that for reaction with NO. No evidence for reaction of N3 with CO was observed, in contrast to previous literature data. Reaction of N3 with O2 was found to be extremely slow, k < 6 x 10(-20) cm3 molecule(-1) s(-1), although this upper limit does not necessarily rule out its occurrence in the atmosphere. Finally, the rate coefficient for reaction of Cl with HN3 was measured using a relative rate method, k = (1.0+/-0.2) x 10(-12) cm3 molecule(-1) s(-1).

  11. Megasonic cleaning: possible solutions for 22nm node and beyond

    NASA Astrophysics Data System (ADS)

    Shende, Hrishi; Singh, Sherjang; Baugh, James; Mann, Raunak; Dietze, Uwe; Dress, Peter

    2011-11-01

    Megasonic energy transfer to the photomask surface is indirectly controlled by process parameters that provide an effective handle to physical force distribution on the photomask surface. A better understanding of the influence of these parameters on the physical force distribution and their effect on pattern damage of fragile mask features can help optimize megasonic energy transfer as well as assist in extending this cleaning technology beyond the 22nm node. In this paper we have specifically studied the effect of higher megasonic frequencies (3 & 4MHz) and media gasification on pattern damage; the effect of cleaning chemistry, media volume flow rate, process time, and nozzle distance to the mask surface during the dispense is also discussed. Megasonic energy characterization is performed by measuring the acoustic energy as well as cavitation created by megasonic energy through sonoluminescence measurements.

  12. Fluorescence microscopy with 6 nm resolution on DNA origami.

    PubMed

    Raab, Mario; Schmied, Jürgen J; Jusuk, Ija; Forthmann, Carsten; Tinnefeld, Philip

    2014-08-25

    Resolution of emerging superresolution microscopy is commonly characterized by the width of a point-spread-function or by the localization accuracy of single molecules. In contrast, resolution is defined as the ability to separate two objects. Recently, DNA origamis have been proven as valuable scaffold for self-assembled nanorulers in superresolution microscopy. Here, we use DNA origami nanorulers to overcome the discrepancy of localizing single objects and separating two objects by resolving two docking sites at distances of 18, 12, and 6 nm by using the superresolution technique DNA PAINT(point accumulation for imaging in nanoscale topography). For the smallest distances, we reveal the influence of localization noise on the yield of resolvable structures that we rationalize by Monte Carlo simulations.

  13. TO packaged 650nm red semiconductor laser with transparent window

    NASA Astrophysics Data System (ADS)

    Xia, Wei; Zhu, Zhen; Li, Peixu; Su, Jian; Zhang, Xin; Xu, Xiangang

    2016-11-01

    Highly uniform solid-phase Zn-diffusion technique was developed to fabricate transparent windows for 650 nm red laser diodes (LDs). The maximum output power was up to 120 mW, which is three times higher than that for LDs without window structure. The LDs showed excellent thermal characteristics and aging reliability with TO-can package. The characteristic temperature was estimated to be 85 K in the temperature range of 25 65 °C. The LDs showed stable operation of 10 mW at a high temperature of 75 °C. After aging test of 2000 h, the elevated operation current was less than 3%, compared to the initial value. The predicted life time was over 10000 h for 10 mW operation at 75 °C.

  14. High performance diode lasers emitting at 780-820 nm

    NASA Astrophysics Data System (ADS)

    Bao, L.; DeVito, M.; Grimshaw, M.; Leisher, P.; Zhou, H.; Dong, W.; Guan, X.; Zhang, S.; Martinsen, R.; Haden, J.

    2012-03-01

    High power 780-820 nm diode lasers have been developed for pumping and material processing systems. This paper presents recent progress in the development of such devices for use in high performance industrial applications. A newly released laser design in this wavelength range demonstrates thermally limited >25W CW power without catastrophic optical mirror damage (COMD), with peak wallplug efficiency ~65%. Ongoing accelerated lifetesting projects a time to 5% failure of ~10 years at 5 and 8 W operating powers for 95 and 200 μm emitter widths, respectively. Preliminary results indicate the presence and competition of a random and wear-out failure mode. Fiber-coupled modules based on arrays of these devices support >100W reliable operation, with a high 56% peak efficiency (ex-fiber) and improved brightness/reliability.

  15. Wide modulation bandwidth terahertz detection in 130 nm CMOS technology

    NASA Astrophysics Data System (ADS)

    Nahar, Shamsun; Shafee, Marwah; Blin, Stéphane; Pénarier, Annick; Nouvel, Philippe; Coquillat, Dominique; Safwa, Amr M. E.; Knap, Wojciech; Hella, Mona M.

    2016-11-01

    Design, manufacturing and measurements results for silicon plasma wave transistors based wireless communication wideband receivers operating at 300 GHz carrier frequency are presented. We show the possibility of Si-CMOS based integrated circuits, in which by: (i) specific physics based plasma wave transistor design allowing impedance matching to the antenna and the amplifier, (ii) engineering the shape of the patch antenna through a stacked resonator approach and (iii) applying bandwidth enhancement strategies to the design of integrated broadband amplifier, we achieve an integrated circuit of the 300 GHz carrier frequency receiver for wireless wideband operation up to/over 10 GHz. This is, to the best of our knowledge, the first demonstration of low cost 130 nm Si-CMOS technology, plasma wave transistors based fast/wideband integrated receiver operating at 300 GHz atmospheric window. These results pave the way towards future large scale (cost effective) silicon technology based terahertz wireless communication receivers.

  16. Pollution Prevention Opportunity Assessment for the SNL/NM cafeterias.

    SciTech Connect

    McCord, Samuel Adam

    2005-12-01

    This Pollution Prevention Opportunity Assessment (PPOA) was conducted for the two Sandia National Laboratories/New Mexico cafeteria facilities between May and August 2005. The primary purpose of this PPOA is to assess waste and resource reduction opportunities and issue Pollution Prevention (P2) recommendations for Sandia's food service facilities. This PPOA contains recommendations for energy, water and resource reduction, as well as material substitution based upon environmentally preferable purchasing. Division 3000 has requested the PPOA report as part of the Division's compliance effort to implement the Environmental Management System (EMS) per DOE Order 450.1. This report contains a summary of the information collected and analyses performed with recommended options for implementation. The SNL/NM P2 Group will work with Division 3000 and the respective cafeteria facilities to implement these options.

  17. Correlating Pulses from Two Spitfire, 800nm Lasers

    SciTech Connect

    Colby, Eric R.; Mcguinness, C.; Zacherl, W.D.; Plettner, T.; /Stanford U., Phys. Dept.

    2008-01-28

    The E163 laser acceleration experiments conducted at SLAC have stringent requirements on the temporal properties of two regeneratively amplified, 800nm, Spitfire laser systems. To determine the magnitude and cause of timing instabilities between the two Ti:Sapphire amplifiers, we pass the two beams through a cross-correlator and focus the combined beam onto a Hamamatsu G1117 photodiode. The photodiode has a bandgap such that single photon processes are suppressed and only the second order, two-photon process produces an observable response. The response is proportional to the square of the intensity. The diode is also useful as a diagnostic to determine the optimal configuration of the compression cavity.

  18. Corneal and skin laser exposures from 1540-nm laser pulses

    NASA Astrophysics Data System (ADS)

    Johnson, Thomas E.; Mitchell, Michael A.; Rico, Pedro J.; Fletcher, David J.; Eurell, Thomas E.; Roach, William P.

    2000-06-01

    Mechanisms of tissue damage are investigated for skin and cornea exposures from 1540 nm ('eye safe') laser single pulses of 0.8 milli-seconds. New skin model data point out the advantages of using the Yucatan mini-pig versus the Yorkshire pig for in-vivo skin laser exposures. Major advantages found include similarities in thickness and melanin content when compared with human skin. Histology from Yucatan mini-pig skin exposures and the calculation of an initial ED50 threshold indicate that the main photon tissue interaction may not be solely due to water absorption. In-vitro corneal equivalents compared well with in-vivo rabbit cornea exposure under similar laser conditions. In-vivo and in-vitro histology show that initial energy deposition leading to damage occurs intrastromally, while epithelial cells show no direct injury due to laser light absorption.

  19. Performance comparison of the 1310nm optical amplifiers

    NASA Astrophysics Data System (ADS)

    Chorchos, Łukasz; Turkiewicz, Jarosław P.

    2016-09-01

    One of the key optical transmission components are optical amplifiers. In this paper studies on the amplification properties of the 1310 nm optical amplifiers are presented. The evaluated optical amplifiers are: semiconductor optical amplifier (SOA) and praseodymium doped fibre amplifier (PDFA). The study is aimed to the dynamic operation in single- and multi- wavelength domain with the high rate signals namely 25 Gbit/s. The maximum obtained gain was 25.0 dB for SOA and 20.9 dB for PDFA. For the SOAs the minimum achieved value of the receiver sensitivity was -11.5 dBm for single channel and -11.5 dBm for DWDM case when for PDFA those values were -11.0 dBm and -10.9 respectively. The main advantage of the PDFA in comparison to the measured SOAs is higher saturation power.

  20. Laser ablation of polymeric materials at 157 nm

    NASA Astrophysics Data System (ADS)

    Costela, A.; García-Moreno, I.; Florido, F.; Figuera, J. M.; Sastre, R.; Hooker, S. M.; Cashmore, J. S.; Webb, C. E.

    1995-03-01

    Results are presented on the ablation by 157 nm laser radiation of polytetrafluoroethylene (PTFE), polyimide, polyhydroxybutyrate (PHB), poly(methyl methacrylate) (PMMA), and poly(2-hydroxyethyl methacrylate) with 1% of ethylene glycol dimethacrylate as a crosslinking monomer. Direct photoetching of PHB and undoped PTFE is demonstrated for laser fluences ranging from 0.05 to 0.8 J/cm2. The dependence of the ablation process on the polymer structure is analyzed, and insight into the ablation mechanism is gained from an analysis of the data using Beer-Lambert's law and the kinetic model of the moving interface. Consideration of the absorbed energy density required to initiate significant ablation suggests that the photoetching mechanism is similar for all the polymers studied.

  1. NM-Scale Anatomy of an Entire Stardust Carrot Track

    NASA Technical Reports Server (NTRS)

    Nakamura-Messenger, K.; Keller, L. P.; Clemett, S. J.; Messenger, S.

    2009-01-01

    Comet Wild-2 samples collected by NASA s Stardust mission are extremely complex, heterogeneous, and have experienced wide ranges of alteration during the capture process. There are two major types of track morphologies: "carrot" and "bulbous," that reflect different structural/compositional properties of the impactors. Carrot type tracks are typically produced by compact or single mineral grains which survive essentially intact as a single large terminal particle. Bulbous tracks are likely produced by fine-grained or organic-rich impactors [1]. Owing to their challenging nature and especially high value of Stardust samples, we have invested considerable effort in developing both sample preparation and analytical techniques tailored for Stardust sample analyses. Our report focuses on our systematic disassembly and coordinated analysis of Stardust carrot track #112 from the mm to nm-scale.

  2. Quantity change in collagen following 830-nm diode laser welding

    NASA Astrophysics Data System (ADS)

    Tang, Jing; O'Callaghan, David; Rouy, Simone; Godlewski, Guilhem; Prudhomme, Michel

    1996-12-01

    The actual mechanism for production of laser welding of tissue is presently unknown, but collagen plays an important role is tissue welded after laser irradiance. The quantity change in collagen extracted from the abdominal aorta of Wistar rats after tissue welding using an 830 nm diode laser was investigated. The collagen contents following repeated pepsin digestion after acetic acid extraction were determined with Sircol collagen assay. Compared with untreated aorta, the collagen content of the treated vessel was obvious decreased immediately after laser irradiation and following an initial increase on day 3, there was a peak at day 10. The results suggest that a part of collagen molecules is denatured by the heat of laser. There is an effect of stimulating collagen synthesis after laser welding with parameters used in this study.

  3. Wind Measurements with a 355 nm Molecular Doppler Lidar

    NASA Technical Reports Server (NTRS)

    Gentry, Bruce M.; Chen, Huailin; Li, Steven X.

    2000-01-01

    A Doppler lidar system based on the molecular double edge technique is described. The system is mounted in a modified van to allow deployment in field operations. The lidar operates with a tripled Nd:YAG laser at 355 nm, a 45cm aperture telescope and a matching azimuth-over-elevation scanner to allow full sky access. Validated atmospheric wind profiles have been measured from 1.8 km to 35 km with a 178 m vertical resolution. The range dependent rms deviation of the horizontal wind speed is 0.4 - 6 m/s. The results of wind speed and direction are in good agreement with balloon sonde wind measurements made simultaneously at the same location.

  4. Discrete plasticity in sub-10-nm-sized gold crystals

    PubMed Central

    Zheng, He; Cao, Ajing; Weinberger, Christopher R.; Huang, Jian Yu; Du, Kui; Wang, Jianbo; Ma, Yanyun; Xia, Younan; Mao, Scott X.

    2010-01-01

    Although deformation processes in submicron-sized metallic crystals are well documented, the direct observation of deformation mechanisms in crystals with dimensions below the sub-10-nm range is currently lacking. Here, through in situ high-resolution transmission electron microscopy (HRTEM) observations, we show that (1) in sharp contrast to what happens in bulk materials, in which plasticity is mediated by dislocation emission from Frank-Read sources and multiplication, partial dislocations emitted from free surfaces dominate the deformation of gold (Au) nanocrystals; (2) the crystallographic orientation (Schmid factor) is not the only factor in determining the deformation mechanism of nanometre-sized Au; and (3) the Au nanocrystal exhibits a phase transformation from a face-centered cubic to a body-centered tetragonal structure after failure. These findings provide direct experimental evidence for the vast amount of theoretical modelling on the deformation mechanisms of nanomaterials that have appeared in recent years. PMID:21266994

  5. High power terahertz generation using 1550 nm plasmonic photomixers

    NASA Astrophysics Data System (ADS)

    Berry, Christopher W.; Hashemi, Mohammad R.; Preu, Sascha; Lu, Hong; Gossard, Arthur C.; Jarrahi, Mona

    2014-07-01

    We present a 1550 nm plasmonic photomixer operating under pumping duty cycles below 10%, which offers significantly higher terahertz radiation power levels compared to previously demonstrated photomixers. The record-high terahertz radiation powers are enabled by enhancing the device quantum efficiency through use of plasmonic contact electrodes, and by mitigating thermal breakdown at high optical pump power levels through use of a low duty cycle optical pump. The repetition rate of the optical pump can be specifically selected at a given pump duty cycle to control the spectral linewidth of the generated terahertz radiation. At an average optical pump power of 150 mW with a pump modulation frequency of 1 MHz and pump duty cycle of 2%, we demonstrate up to 0.8 mW radiation power at 1 THz, within each continuous wave radiation cycle.

  6. Fabrication of sub-15 nm aluminum wires by controlled etching

    NASA Astrophysics Data System (ADS)

    Morgan-Wall, T.; Hughes, H. J.; Hartman, N.; McQueen, T. M.; Marković, N.

    2014-04-01

    We describe a method for the fabrication of uniform aluminum nanowires with diameters below 15 nm. Electron beam lithography is used to define narrow wires, which are then etched using a sodium bicarbonate solution, while their resistance is simultaneously measured in-situ. The etching process can be stopped when the desired resistance is reached, and can be restarted at a later time. The resulting nanowires show a superconducting transition as a function of temperature and magnetic field that is consistent with their smaller diameter. The width of the transition is similar to that of the lithographically defined wires, indicating that the etching process is uniform and that the wires are undamaged. This technique allows for precise control over the normal state resistance and can be used to create a variety of aluminum nanodevices.

  7. Characterization of a THz CW spectrometer pumped at 1550 nm

    NASA Astrophysics Data System (ADS)

    Yeo, Woon-Gi; Nahar, Niru K.

    2015-07-01

    We present an evaluation of a cost-effective THz CW spectrometer pumped at 1550 nm wavelengths with a fixed delay line. To study the spectral competence of the spectrometer, transmission data is obtained for various organic and inorganic samples. Spectral comparisons of the samples are presented by using THz time domain spectroscopy and vector network analyzer (VNA). Despite the capability of highly resolved transmission spectroscopy, our current system reveals the uncertainty in interferometric output data for phase analysis. Here, we identify the effect of fringing space of raw output data toward frequency resolution, phase analysis, and data acquisition time. We also propose the proper delay line setup for phase analysis for this type of spectrometers.

  8. Multiple product pathways in photodissociation of nitromethane at 213 nm

    SciTech Connect

    Sumida, Masataka; Kohge, Yasunori; Yamasaki, Katsuyoshi; Kohguchi, Hiroshi

    2016-02-14

    In this paper, we present a photodissociation dynamics study of nitromethane at 213 nm in the π → π{sup *} transition. Resonantly enhanced multiphoton ionization spectroscopy and ion-imaging were applied to measure the internal state distributions and state-resolved scattering distributions of the CH{sub 3}, NO(X {sup 2}Π, A {sup 2}Σ{sup +}), and O({sup 3}P{sub J}) photofragments. The rotationally state-resolved scattering distribution of the CH{sub 3} fragment showed two velocity components, of which the slower one decreased the relative intensity as the rotational and vibrational excitations. The translational energy distribution of the faster CH{sub 3} fragment indicated the production of the NO{sub 2} counter-product in the electronic excited state, wherein 1 {sup 2}B{sub 2} was the most probable. The NO(v = 0) fragment exhibited a bimodal translational energy distribution, whereas the NO(v = 1 and 2) fragment exhibited a single translational energy component with a relatively larger internal energy. The translational energy of a portion of the O({sup 3}P{sub J}) photofragment was found to be higher than the one-photon dissociation threshold, indicating the two-photon process involved. The NO(A {sup 2}Σ{sup +}) fragment, which was detected by ionization spectroscopy via the Rydberg ←A {sup 2}Σ{sup +} transition, also required two-photon energy. These experimental data corroborate the existence of competing photodissociation product pathways, CH{sub 3} + NO{sub 2},CH{sub 3} + NO + O,CH{sub 3}O + NO, and CH{sub 3}NO + O, following the π → π{sup *} transition. The origins of the observed photofragments are discussed in this report along with recent theoretical studies and previous dynamics experiments performed at 193 nm.

  9. New single-layer positive photoresists for 193-nm photolithography

    NASA Astrophysics Data System (ADS)

    Okoroanyanwu, Uzodinma; Shimokawa, Tsutomu; Byers, Jeff D.; Medeiros, David R.; Willson, C. Grant; Niu, Qingshang J.; Frechet, Jean M. J.; Allen, Robert D.

    1997-07-01

    New series of chemically amplified, single layer, positive tone photoresists for 193 nm lithography have been developed. These resists were formulated from a series of cycloaliphatic co- and terpolymers of 2-methyl propyl bicyclo(2.2.1)hept-2- ene-5-carboxylate (carbo-tert-butoxynorbornene), bicyclo(2.2.1)hept-2-ene carboxylic acid (norbornene carboxylic acid), 8-methyl-8-carboxy tetracyclo(4,4,0.12,5,17,10)dodec-3-ene (methyltetracyclododecene carboxylic acid), norbornenemethanol, and maleic anhydride, which were synthesized by free radical, vinyl addition and ring opening metathesis polymerization techniques. The polymers derived from ring opening metathesis polymerization have bee successfully hydrogenated to provide yet another member of this group of materials. The cycloaliphatic polymer backbones provide etch resistance, mechanical properties and stability to radiation. The lithographic function is provided by carefully tailored pendant groups, which include an acid functionality that is masked by protecting groups that undergo acid catalyzed thermolysis as well as polar groups that influence the adhesion, wetability and dissolution properties of the polymer. The polymers are soluble in common organic solvents and have glass transition temperatures ranging from less than 60 degrees Celsius to higher than 250 degrees Celsius depending on their specific structure and mode of polymerization. They are at least as transparent at 193 nm as the corresponding acrylics. Their dry etch resistance varies with the formulation, but the base polymers etch more slowly than novolac under conditions typically used to pattern polysilicon. Upon exposure and baking, the resists have demonstrated high sensitivities (9-25 mJ/cm2), and 0.16 micrometer features have bean resolved.

  10. Lasing at 300 nm and below: Optical challenges and perspectives

    SciTech Connect

    Garzella, D.; Couprie, M.E. |; Billardon, M.

    1995-12-31

    The FEL experiment in the visible and near UV on the Super ACO storage ring has given, since 1989, important informations on the SRFEL dynamics and, furthermore, a very good beam stability has been achieved. In addition, the operation at 350 nm with this good stability and a long beam lifetime allowed us to perform the first user experiment in biology and to start with a campaign for using the laser as photons source for experiments in other domains, coupling FEL light and the Synchrotron Radiation. For this, FEL starts to be very competitive with respect to the other conventional laser sources, provided that it could oscillate further in the UV, say at 300 nm and below. So, the real challenge is now given by the lasing at shorter wavelengths and, for this, by the optical technology existing nowadays. Since 1992 the efforts have been concentrating to look for every kind of solution allowing us to overcome the problem of having a very low gain. From an optical point of view, in the range of wavelengths explored, there is a lack of transparents dielectric materials for substrates and coatings. Substrates are required at the same time to be relatively not absorbing (a few tens 10{sup -6}), to have a very good surface quality (RMS roughness below 10 {Angstrom}) because of scattering losses dramatically increasing in this spectral range and, due to the thermal load of the undulator emission, to have adequate thermal characteristics. In order to fulfill all these requirements, a good characterisation and modelisation of the substrates is needed, especially to correlate thermal loading and mechanical deformations from one hand, and roughness and scattering losses from the other hand. Coatings must be not absorbing too and, above all, the most amorphous as possible (this could be obtained with IBS deposition technique), in order to insure a good reproduction of the substrate roughness at the interfaces and on the top layer and an higher resistance to the XUV photons load.

  11. Iodide-mediated photooxidation of arsenite under 254 nm irradiation.

    PubMed

    Yeo, Jiman; Choi, Wonyong

    2009-05-15

    The preoxidation of As(III) to As(V) is a desirable process to increase the removal efficiency of arsenic in water treatment In this work, the photooxidation of As(III) under 254 nm irradiation was investigated in the concentration range of 1-1000 microM in the presence of potassium iodide (typically 100 microM). Although the direct photooxidation of As(III) in water was negligible, the presence of iodide dramatically enhanced the oxidation rate. The quantitative conversion of As(III) to As(V) was achieved. The quantum yields of As(III) photooxidation ranged from 0.08 to 0.6, depending on the concentration of iodide and As(III). The excitation of iodides under 254 nm irradiation led to the generation of iodine atoms and triiodides, which seem to be involved in the oxidation process of As(III). Because the efficiency of iodine atom generation is highly dependent on the presence of suitable electron acceptors,the photooxidation of As(III) was efficient in an air- or N2O-saturated solution but markedly reduced in the N2-saturated solution. The production of H2O2 was also accompanied by the generation of As(V). The addition of excess methanol (OH radical scavenger) did not reduce the photooxidation rate at all, which ruled out the possibility of hydroxyl radical involvement. It was found that the in situ photogenerated triiodides oxidize As(III) with regenerating iodides by completing a cycle. The proposed UV254/KI/As(III) process is essentially an iodide-mediated photocatalysis.

  12. Enhancing chemical reactions

    DOEpatents

    Morrey, John R.

    1978-01-01

    Methods of enhancing selected chemical reactions. The population of a selected high vibrational energy state of a reactant molecule is increased substantially above its population at thermal equilibrium by directing onto the molecule a beam of radiant energy from a laser having a combination of frequency and intensity selected to pump the selected energy state, and the reaction is carried out with the temperature, pressure, and concentrations of reactants maintained at a combination of values selected to optimize the reaction in preference to thermal degradation by transforming the absorbed energy into translational motion. The reaction temperature is selected to optimize the reaction. Typically a laser and a frequency doubler emit radiant energy at frequencies of .nu. and 2.nu. into an optical dye within an optical cavity capable of being tuned to a wanted frequency .delta. or a parametric oscillator comprising a non-centrosymmetric crystal having two indices of refraction, to emit radiant energy at the frequencies of .nu., 2.nu., and .delta. (and, with a parametric oscillator, also at 2.nu.-.delta.). Each unwanted frequency is filtered out, and each desired frequency is focused to the desired radiation flux within a reaction chamber and is reflected repeatedly through the chamber while reactants are fed into the chamber and reaction products are removed therefrom.

  13. Algorithm for reaction classification.

    PubMed

    Kraut, Hans; Eiblmaier, Josef; Grethe, Guenter; Löw, Peter; Matuszczyk, Heinz; Saller, Heinz

    2013-11-25

    Reaction classification has important applications, and many approaches to classification have been applied. Our own algorithm tests all maximum common substructures (MCS) between all reactant and product molecules in order to find an atom mapping containing the minimum chemical distance (MCD). Recent publications have concluded that new MCS algorithms need to be compared with existing methods in a reproducible environment, preferably on a generalized test set, yet the number of test sets available is small, and they are not truly representative of the range of reactions that occur in real reaction databases. We have designed a challenging test set of reactions and are making it publicly available and usable with InfoChem's software or other classification algorithms. We supply a representative set of example reactions, grouped into different levels of difficulty, from a large number of reaction databases that chemists actually encounter in practice, in order to demonstrate the basic requirements for a mapping algorithm to detect the reaction centers in a consistent way. We invite the scientific community to contribute to the future extension and improvement of this data set, to achieve the goal of a common standard.

  14. Modeling of surface reactions

    SciTech Connect

    Ray, T.R.

    1993-01-01

    Mathematical models are used to elucidate properties of the monomer-monomer and monomer-dimer type chemical reactions on a two-dimensional surface. The authors use mean-field and lattice gas models, detailing similarities and differences due to correlations in the lattice gas model. The monomer-monomer, or AB surface reaction model, with no diffusion, is investigated for various reaction rates k. Study of the exact rate equations reveals that poisoning always occurs if the adsorption rates of the reactants are unequal. If the adsorption rates of the reactants are equal, simulations show slow poisoning, associated with clustering of reactants. This behavior is also shown for the two-dimensional voter model. The authors analyze precisely the slow poisoning kinetics by an analytic treatment for the AB reaction with infinitesimal reaction rate, and by direct comparison with the voter model. They extend the results to incorporate the effects of place-exchange diffusion, and they compare the AB reaction with infinitesimal reaction rate and no diffusion to the voter model with diffusion at rate 1/2. They also consider the relationship of the voter model to the monomer-dimer model, and investigate the latter model for small reaction rates. The monomer-dimer, or AB[sub 2] surface reaction model is also investigated. Specifically, they consider the ZGB-model for CO-oxidation, and in generalizations of this model which include adspecies diffusion. A theory of nucleation to describe properties of non-equilibrium first-order transitions, specifically the evolution between [open quote]reactive[close quote] steady states and trivial adsorbing states, is derived. The behavior of the [open quote]epidemic[close quote] survival probability, P[sub s], for a non-poisoned patch surrounded by a poisoned background is determined below the poisoning transition.

  15. Picosecond pulses in deep ultraviolet (257.5 nm and 206 nm) and mid-IR produced by a high-power 100 kHz solid-state thin-disk laser

    NASA Astrophysics Data System (ADS)

    Turčičová, Hana; Novák, Ondřej; Smrž, Martin; Miura, Taisuke; Endo, Akira; Mocek, TomáÅ.¡

    2016-04-01

    We report on the generation of picosecond deep ultraviolet pulses at 257.5 nm and 206 nm produced as the fourth and fifth harmonic frequencies of the diode-pumped Yb:YAG thin-disk laser at the fundamental wavelength of 1030 nm. We present a proposal for a picosecond pulse mid-IR source tunable between 2 and 3 μm. The laser at the fundamental wavelength is based on a chirped-pulse amplification of pulses of a sub-ps laser oscillator in a regenerative amplifier with a thin-disk active medium. The diode pumping at the zero phonon line is used. The output beam is close to the fundamental spatial mode and the pulses are characterized by a 100 kHz repetition frequency, less than 4 ps pulse duration and <=1 mJ pulse energy. The fundamental beam is split and the main part is first frequency doubled in an LBO crystal. Subsequently the fourth harmonic frequency (257.5 nm) is produced by frequency doubling of the second harmonic frequency in BBO/CLBO crystals. The remaining part of the fundamental beam is summed with the fourth harmonic beam in the 1ω+4ω quantum reaction in a further CLBO crystal for the fifth harmonic frequency (206 nm) production. The design for the generation of the mid-IR wavelengths is based on the optical parametric generation and amplification. The first stage contains a temperature tuned PPLN, the following amplification stages are based on KTA crystals tuned by angle. Picosecond output pulses tunable between 2 and 3 μm at an average power of 10 W are proposed.

  16. Cycloaddition reactions of ICNO

    NASA Astrophysics Data System (ADS)

    Pasinszki, Tibor; Krebsz, Melinda; Hajgató, Balázs

    2009-05-01

    The mechanism and selectivity of cycloaddition reactions of iodonitrile oxide, ICNO, have been studied with theoretical methods for the first time using MR-AQCC coupled-cluster and B3LYP DFT methods. Calculations have predicted that the favoured ICNO dimerisation process is a multi-step reaction to diiodofuroxan involving dinitrosoethylene-like intermediates. The ICNO cycloaddition with nitriles and ethynyl derivatives is a synchronous process favouring the formation of 1,2,4-oxadiazole and 1,2-oxazole derivatives, respectively. The cycloaddition reactions of ICNO have been studied experimentally by generating ICNO from AgCNO and iodine. Diiodofuroxan is obtained, however, even at the presence of nitriles.

  17. NEUTRONIC REACTION SYSTEM

    DOEpatents

    Wigner, E.P.

    1963-09-01

    A nuclear reactor system is described for breeding fissionable material, including a heat-exchange tank, a high- and a low-pressure chamber therein, heat- exchange tubes connecting these chambers, a solution of U/sup 233/ in heavy water in a reaction container within the tank, a slurry of thorium dioxide in heavy water in a second container surrounding the first container, an inlet conduit including a pump connecting the low pressure chamber to the reaction container, an outlet conduit connecting the high pressure chamber to the reaction container, and means of removing gaseous fission products released in both chambers. (AEC)

  18. UV absorption spectrum of the ClO dimer (Cl2O2) between 200 and 420 nm.

    PubMed

    Papanastasiou, Dimitrios K; Papadimitriou, Vassileios C; Fahey, David W; Burkholder, James B

    2009-12-10

    The UV photolysis of Cl(2)O(2) (dichlorine peroxide) is a key step in the catalytic destruction of polar stratospheric ozone. In this study, the gas-phase UV absorption spectrum of Cl(2)O(2) was measured using diode array spectroscopy and absolute cross sections, sigma, are reported for the wavelength range 200-420 nm. Pulsed laser photolysis of Cl(2)O at 248 nm or Cl(2)/Cl(2)O mixtures at 351 nm at low temperature (200-228 K) and high pressure (approximately 700 Torr, He) was used to produce ClO radicals and subsequently Cl(2)O(2) via the termolecular ClO self-reaction. The Cl(2)O(2) spectrum was obtained from spectra recorded following the completion of the gas-phase ClO radical chemistry. The spectral analysis used observed isosbestic points at 271, 312.9, and 408.5 nm combined with reaction stoichiometry and chlorine mass balance to determine the Cl(2)O(2) spectrum. The Cl(2)O(2) UV absorption spectrum peaks at 244.5 nm with a cross section of 7.6(-0.5)(+0.8) x 10(-18) cm(2) molecule(-1) where the quoted error limits are 2sigma and include estimated systematic errors. The Cl(2)O(2) absorption cross sections obtained for wavelengths in the range 300-420 nm are in good agreement with the Cl(2)O(2) spectrum reported previously by Burkholder et al. (J. Phys. Chem. A 1990, 94, 687) and significantly higher than the values reported by Pope et al. (J. Phys. Chem. A 2007, 111, 4322). A possible explanation for the discrepancy in the Cl(2)O(2) cross section values with the Pope et al. study is discussed. Representative, atmospheric photolysis rate coefficients are calculated and a range of uncertainty estimated based on the determination of sigma(Cl(2)O(2))(lambda) in this work. Although improvements in our fundamental understanding of the photochemistry of Cl(2)O(2) are still desired, this work indicates that major revisions in current atmospheric chemical mechanisms are not required to simulate observed polar ozone depletion.

  19. A Photo-Triggered Traceless Staudinger-Bertozzi Ligation Reaction.

    PubMed

    Hu, Peng; Feng, Tianshi; Yeung, Chi-Chung; Koo, Chi-Kin; Lau, Kai-Chung; Lam, Michael H W

    2016-08-08

    The use of light to control the course of a chemical/biochemical reaction is an attractive idea because of its ease of administration with high precision and fine spatial resolution. Staudinger ligation is one of the commonly adopted conjugation processes that involve a spontaneous reaction between azides and arylphosphines to form iminophosphoranes, which further hydrolyze to give stable amides. We designed an anthracenylmethyl diphenylphosphinothioester (1) that showed promising Staudinger ligation reactivity upon photo-excitation. Broadband photolysis at 360-400 nm in aqueous organic solvents induced heterolytic cleavage of its anthracenylmethyl-phosphorus bond, releasing a diphenylphosphinothioester (2) as an efficient traceless Staudinger-Bertozzi ligation reagent. The quantum yield of such a photo-induced heterolytic bond-cleavage at the optimal wavelength of photolysis (376 nm) at room temperature is ≥0.07. This work demonstrated the feasibility of photocaging arylphosphines to realize the photo-triggering of the Staudinger ligation reaction.

  20. A Sounding Rocket Mission Concept to Acquire High-Resolution Radiometric Spectra Spanning the 9 nm - 31 nm Wavelength Range

    NASA Technical Reports Server (NTRS)

    Krause, L. Habash; Cirtain, Jonathan; McGuirck, Michael; Pavelitz, Steven; Weber, Ed.; Winebarger, Amy

    2012-01-01

    When studying Solar Extreme Ultraviolet (EUV) emissions, both single-wavelength, two- dimensional (2D) spectroheliograms and multi-wavelength, one-dimensional (1D) line spectra are important, especially for a thorough understanding of the complex processes in the solar magnetized plasma from the base of the chromosphere through the corona. 2D image data are required for a detailed study of spatial structures, whereas radiometric (i.e., spectral) data provide information on relevant atomic excitation/ionization state densities (and thus temperature). Using both imaging and radiometric techniques, several satellite missions presently study solar dynamics in the EUV, including the Solar Dynamics Observatory (SDO), Hinode, and the Solar-Terrestrial Relations Observatory (STEREO). The EUV wavelengths of interest typically span 9 nm to 31 nm, with the shorter wavelengths being associated with the hottest features (e.g., intense flares and bright points) and the longer wavelengths associated with cooler features (e.g., coronal holes and filaments). Because the optical components of satellite instruments degrade over time, it is not uncommon to conduct sounding rocket underflights for calibration purposes. The authors have designed a radiometric sounding rocket payload that could serve as both a calibration underflight for and a complementary scientific mission to the upcoming Solar Ultraviolet Imager (SUVI) mission aboard the GOES-R satellite (scheduled for a 2015 launch). The challenge to provide quality radiometric line spectra over the 9-31 nm range covered by SUVI was driven by the multilayer coatings required to make the optical components, including mirrors and gratings, reflective over the entire range. Typically, these multilayers provide useful EUV reflectances over bandwidths of a few nm. Our solution to this problem was to employ a three-telescope system in which the optical components were coated with multilayers that spanned three wavelength ranges to cover

  1. Photo-CIDNP of Photosyntheitc Reaction Centers

    SciTech Connect

    Ann. E. McDermott

    2005-10-22

    Studies of Photochemically Induced Dynamic Nuclear Polarization in Photosynthetic Bacterial Reaction Centers: Wavelength and Time Dependence Solid-state NMR spectra of quinone-reduced photosynthetic bacterial reaction centers (RCs) and chromatophores exhibit certain strongly enhanced lines under illumination, a result of photochemically induced dynamic nuclear polarization (photo-CIDNP). This technique offers a new method to investigate photosynthetic electronic transactions while retaining the NMR advantages of narrow linewidths and site-specific resolution. Pulsed laser illumination at 532 nm was used as the basis for time resolved photo-CIDNP experiments, a technique not previously published for solid-state photosynthetic systems. These measurements offer insight about the origin of the polarization effects.

  2. Kinetics of sub-2 nm TiO2 particle formation in an aerosol reactor during thermal decomposition of titanium tetraisopropoxide

    NASA Astrophysics Data System (ADS)

    Wang, Yang; Liu, Pai; Fang, Jiaxi; Wang, Wei-Ning; Biswas, Pratim

    2015-03-01

    Particle size distribution measurements from differential mobility analyzers (DMAs) can be utilized to study particle formation mechanisms. However, knowledge on the initial stages of particle formation is incomplete, since in conventional DMAs, the Brownian broadening effect limits their ability to measure sub-2 nm-sized particles. Previous studies have demonstrated the capability of high-flow DMAs, such as the Half Mini DMAs, to measure sub-2 nm particles with significantly higher resolutions than conventional DMAs. A Half Mini DMA was applied to study the kinetics of sub-2 nm TiO2 nanoparticle formation in a furnace aerosol reactor, through the thermal decomposition of titanium tetraisopropoxide (TTIP). The influence of parameters such as reaction temperature, residence time, precursor concentration, and the introduction of bipolar charges on sub-2 nm particle size distributions were studied. A first order reaction rate derived from the dependence of size distributions on reaction temperature matched well with existing literature data. The change in precursor residence time and precursor concentration altered the size distributions correspondingly, indicating the occurrence of TTIP thermal decomposition. The introduction of bipolar charges in aerosol reactors enhanced the consumption of reactants, possibly due to ion-induced nucleation and induced dipole effects.

  3. Bad Reaction to Cosmetics?

    MedlinePlus

    ... Devices Radiation-Emitting Products Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products For Consumers Home For Consumers ... Reactions From Cosmetics More in Consumer Updates Animal & Veterinary Children's Health Cosmetics Dietary Supplements Drugs Food Medical ...

  4. Reactor for exothermic reactions

    DOEpatents

    Smith, Jr., Lawrence A.; Hearn, Dennis; Jones, Jr., Edward M.

    1993-01-01

    A liquid phase process for oligomerization of C.sub.4 and C.sub.5 isoolefins or the etherification thereof with C.sub.1 to C.sub.6 alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120.degree. to 300.degree. F. Wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

  5. Untoward penicillin reactions

    PubMed Central

    Guthe, T.; Idsöe, O.; Willcox, R. R.

    1958-01-01

    The literature on untoward reactions following the administration of penicillin is reviewed. These reactions, including a certain number of deaths which have been reported, are of particular interest to health administrations and to WHO in view of the large-scale programmes for controlling the treponematoses which are now under way—programmes affecting millions of people in many parts of the world. The most serious problems are anaphylactic sensitivity phenomena and superinfection or cross-infection with penicillin-resistant organisms, and the reactions involved range in intensity from the mildest to the fatal; the incidence of the latter is estimated at 0.1-0.3 per million injections. The authors point out that with increasing use of penicillin, more persons are likely to become sensitized and the number of reactions can therefore be expected to rise. The best prevention against such an increase is the restriction of the unnecessary use of penicillin. PMID:13596877

  6. Translated chemical reaction networks.

    PubMed

    Johnston, Matthew D

    2014-05-01

    Many biochemical and industrial applications involve complicated networks of simultaneously occurring chemical reactions. Under the assumption of mass action kinetics, the dynamics of these chemical reaction networks are governed by systems of polynomial ordinary differential equations. The steady states of these mass action systems have been analyzed via a variety of techniques, including stoichiometric network analysis, deficiency theory, and algebraic techniques (e.g., Gröbner bases). In this paper, we present a novel method for characterizing the steady states of mass action systems. Our method explicitly links a network's capacity to permit a particular class of steady states, called toric steady states, to topological properties of a generalized network called a translated chemical reaction network. These networks share their reaction vectors with their source network but are permitted to have different complex stoichiometries and different network topologies. We apply the results to examples drawn from the biochemical literature.

  7. Common Reactions After Trauma

    MedlinePlus

    ... Loss of intimacy or feeling detached Recovery from stress reactions Turn to your family and friends when ... someone is thinking about killing themselves, call the Suicide Prevention Lifeline 1-800-273-TALK (8255) http:// ...

  8. Reaction wheel assembly

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The fabrication and testing of three reaction wheels with associated drive and system monitoring electronics and brushless dc spin motors are discussed; the wheels are intended for use in a teleoperator simulator. Test results are included as graphs.

  9. Reactor for exothermic reactions

    DOEpatents

    Smith, L.A. Jr.; Hearn, D.; Jones, E.M. Jr.

    1993-03-02

    A liquid phase process is described for oligomerization of C[sub 4] and C[sub 5] isoolefins or the etherification thereof with C[sub 1] to C[sub 6] alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300 F. Wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

  10. Oral Hypersensitivity Reactions

    MedlinePlus

    ... often flavored with agents like cinnamon, peppermint or menthol, which can trigger hypersensitivity reactions in susceptible individuals. ... potential allergens such as cinnamon, peppermint, eugenol and menthol. Even dental floss and denture cleansers may contain ...

  11. Iodine Clock Reaction.

    ERIC Educational Resources Information Center

    Mitchell, Richard S.

    1996-01-01

    Describes a combination of solutions that can be used in the study of kinetics using the iodine clock reaction. The combination slows down degradation of the prepared solutions and can be used successfully for several weeks. (JRH)

  12. Response reactions: equilibrium coupling.

    PubMed

    Hoffmann, Eufrozina A; Nagypal, Istvan

    2006-06-01

    It is pointed out and illustrated in the present paper that if a homogeneous multiple equilibrium system containing k components and q species is composed of the reactants actually taken and their reactions contain only k + 1 species, then we have a unique representation with (q - k) stoichiometrically independent reactions (SIRs). We define these as coupling reactions. All the other possible combinations with k + 1 species are the coupled reactions that are in equilibrium when the (q - k) SIRs are in equilibrium. The response of the equilibrium state for perturbation is determined by the coupling and coupled equilibria. Depending on the circumstances and the actual thermodynamic data, the effect of coupled equilibria may overtake the effect of the coupling ones, leading to phenomena that are in apparent contradiction with Le Chatelier's principle.

  13. Skin Reactions to Cold

    PubMed Central

    Talpash, Orest

    1976-01-01

    Although skin reactions to cold are seen surprisingly infrequently in Canada, it is important to manage them correctly when they do occur. Frostbite, cold urticarias, Raynaud's disease and phenomenon, and several miscellaneous changes are discussed. PMID:21308019

  14. Chemisorption And Precipitation Reactions

    EPA Science Inventory

    The transport and bioavailability of chemical components within soils is, in part, controlled by partitioning between solids and solution. General terms used to describe these partitioning reactions include chemisorption and precipitation. Chemisorption is inclusive of the suit...

  15. An Illuminating Reaction.

    ERIC Educational Resources Information Center

    Matthews, Catherine E.

    1996-01-01

    Describes the use of carbide lights as an excellent mechanism for introducing or reviewing many basic chemistry concepts including elements and compounds, endothermic and exothermic reactions, physical and chemical changes, and balancing chemical equations. (JRH)

  16. A kinetics investigation of several reactions involving chlorine containing compounds

    NASA Technical Reports Server (NTRS)

    Davis, D. D.

    1978-01-01

    The technique of flash photolysis-resonance fluorescence was utilized to study nine reactions of stratospheric importance. The tropospheric degradation reactions of seven halogenated hydrocarbons were studied to assess their possible influx into the stratosphere. There are reactions of either Cl, OH, or O(3P) species with hydrogenated species, O3 or chlorinated compounds. Apart from the kinetic measurements, the quantum yield for the production of O(1D) from O3 in the crucial wavelength region of 293 to 316.5 nm was studied by utilizing a narrow wavelength laser as the photolysis source. The product formation was monitored by measuring the fluorescence of NO2 formed through O(1D) reaction with N2O followed by NO reaction with O3 to give NO2.

  17. [Occurrence of drug reactions].

    PubMed

    Pastorello, E; Qualizza, R M; Luraghi, M T; Ispano, M; Villa, A M; Ortolani, C; Zanussi, C

    1986-01-01

    The aim of this prospective study was to evaluate the incidence of allergic reactions to drugs compared to other kinds of medical emergencies admitted to the main Hospital in Milan during a 6 months period. At the same time we drew a list of drugs most frequently involved in allergic reactions, and a list of the most frequent symptoms. Using special forms, the medical staff collected patients' data: age, history of atopy, identification of the drug causing the reaction, and any previous reactions. Among 11,407 cases of medical emergencies, we found 163 (1.43%) patients showing drug reactions: the mean age was 27.3; 58.90% were female; atopy was present in 16.56%. The drugs most frequently involved were: pyrazon group (22%); ASA (20.86%); penicillin and derivatives (9.20%); sulfa drugs (6.14%); group B vitamins (4.30%); tetanus toxoid (4.30%); hyposensitizing extracts (3.68%); propionic acid derivatives (2.46%); paracetamol (1.84%); indomethacin (1.23%); rifampicin (1.23%); erythromycin (1.23%); glafenine (1.23%); others (17.80%). Urticaria and/or angioedema were the most frequent symptoms (86.51%), then anaphylactic shock (9.81%) and asthma (3.68%) with regard to anaphylactic shock only 6.20% of the patients had had a previous reaction to the same drug. From these data we can see that the incidence of drug reactions is very low compared to other medical emergencies; penicillin evidenced fewer reactions than expected, while the pyrazon group and ASA confirmed the data from literature.

  18. Anaphylactoid reaction to ethanol.

    PubMed

    Kelso, J M; Keating, M U; Squillace, D L; O'Connell, E J; Yunginger, J W; Sachs, M I

    1990-05-01

    We studied a 14-year-old boy who developed a pruritic rash and facial swelling after ingestion of beer or wine. A blinded challenge with purified ethanol was positive demonstrating ethanol itself to be the offending agent. An IgE-mediated reaction to ethanol or one of its metabolites as a hapten is possible, or the reaction may involve unusual metabolism of ethanol with accumulation of acetaldehyde and/or direct mast cell degranulation.

  19. Oxygen evolution reaction catalysis

    DOEpatents

    Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.

    2016-09-06

    An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

  20. UV 380 nm Reflectivity of the Earth's Surface

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Celarier, E.; Larko, D.

    2000-01-01

    The 380 nm radiance measurements of TOMS (Total Ozone Mapping Spectrometer) have been converted into a global data set of daily (1979 to 1992) Lambert equivalent reflectivities R of the Earth's surface and boundary layer (clouds, aerosols, surface haze, and snow/ice). Since UV surface reflectivity is between 2 and 8% for both land and water during all seasons of the year (except for ice and snow cover), reflectivities larger than the surface value indicates the presence of clouds, haze, or aerosols in the satellite field of view. Statistical analysis of 14 years of daily data show that most snow/ice-free regions of the Earth have their largest fraction of days each year when the reflectivity is low (R less than 10%). The 380 nm reflectivity data shows that the true surface reflectivity is 2 to 3% lower than the most frequently occurring reflectivity value for each TOMS scene. The most likely cause of this could be a combination of frequently occurring boundary-layer water or aerosol haze. For most regions, the observation of extremely clear conditions needed to estimate the surface reflectivity from space is a comparatively rare occurrence. Certain areas (e.g., Australia, southern Africa, portions of northern Africa) are cloud-free more than 80% of the year, which exposes these regions to larger amounts of UV radiation than at comparable latitudes in the Northern Hemisphere. Regions over rain-forests, jungle areas, Europe and Russia, the bands surrounding the Arctic and Antarctic regions, and many ocean areas have significant cloud cover (R greater than 15%) more than half of each year. In the low to middle latitudes, the areas with the heaviest cloud cover (highest reflectivity for most of the year) are the forest areas of northern South America, southern Central America, the jungle areas of equatorial Africa, and high mountain regions such as the Himalayas or the Andes. The TOMS reflectivity data show the presence of large nearly clear ocean areas and the effects

  1. Lactones in 193 nm resists: What do they do?

    NASA Astrophysics Data System (ADS)

    Ito, Hiroshi; Truong, Hoa D.; Brock, Phil J.

    2008-03-01

    Lactones are almost ubiquitously employed in 193 nm resists to increase the polarity of hydrophobic alicyclic polymers. What else do lactones do in 193 nm resists? We studied the behavior of methacrylate (MA) resists consisting of different protecting groups, hexafluoroalcohols, and norbornane lactone methacrylate (NLM, 2-oxo-3-oxatricyclo[4.2.1.04,8]nonan-5-yl methacrylate). When the protecting group is large [ethylcyclooctyl (ECO) and methyladamantyl (MAd)], thinning of the resist film that occurs in highly exposed areas upon postexposure bake (PEB) is significantly smaller than what is expected from the polymer composition. When the concentration of isopropylhexafluoroalcohol methacrylate (iPrHFAMA) is increased in the ECOMA-NLM polymer, the thinning increases and reaches 100% of theory and the ECOMA-norbornenehexafluoroalcohol methacrylate (NBHFAMA) resist loses quantitative thickness in highly-exposed areas upon PEB at 90 °C. This indicates that small lactones which are more basic than esters can trap deprotection fragments especially when the protecting group is large. Such entrapment was detected by IR spectroscopy and also observed at temperatures as high as 200 °C in thermogravimetric analysis (TGA). Incorporation of lactone appears to decrease the bake temperature sensitivity and the sensitivity of the resist perhaps due to trapping of photochemically generated acids by basic lactone. The lactone ring can be hydrolyzed during aqueous base development but does not seem to affect the dissolution rate, indicating that hydrolysis occurs in aqueous base solution after dissolution. Poly(methacrylic acid-NLM) dissolves as fast as poly(methacrylic acid) in 0.26 N tetramethylammonium hydroxide (TMAH) aqueous solution. While exposed P(ECOMA 47-NLM 53) resist dissolves in 0.26 N developer at about the same rate as authentically prepared poly(methacrylic acid 47-NLM 53), the dissolution rate of highly-exposed P(MAdMA 44-NLM 56) resist is much slower, indicating

  2. Laser-Matter Interactions with a 527 nm Drive

    SciTech Connect

    Glenzer, S; Niemann, C; Witman, P; Wegner, P; Mason, D; Haynam, C; Parham, T; Datte, P

    2007-02-16

    The primary goal of this Exploratory Research is to develop an understanding of laser-matter interactions with 527-nm light (2{omega}) for studies of interest to numerous Laboratory programs including inertial confinement fusion (ICF), material strength, radiation transport, and hydrodynamics. In addition, during the course of this work we will develop the enabling technology and prototype instrumentation to diagnose a high fluence laser beam for energy, power, and near field intensity profile at 2{omega}. Through this Exploratory Research we have established an extensive experimental and modeling data base on laser-matter interaction with 527 nm laser light (2{omega}) in plasma conditions of interest to numerous Laboratory programs. The experiments and the laser-plasma interaction modeling using the code pF3D have shown intensity limits and laser beam conditioning requirements for future 2{omega} laser operations and target physics experiments on the National Ignition Facility (NIF). These findings have set requirements for which present radiation-hydrodynamic simulations indicate the successful generation of relevant pressure regimes in future 2{omega} experiments. To allow these experiments on the NIF, optics and optical mounts were prepared for the 18mm Second Harmonic Generation Crystal (SHG crystal) that would provide the desired high conversion efficiency from 1{omega} to 2{omega}. Supporting experimental activities on NIF included high-energy 1{omega} shots at up to 22kJ/beamline (4MJ full NIF 1{omega} equivalent energy) that demonstrated, in excess, the 1{omega} drive capability of the main laser that is required for 2{omega} operations. Also, a very extensive 3{omega} campaign was completed (see ''The National Ignition Facility Laser Performance Status'' UCRL-JRNL-226553) that demonstrated that not only doubling the laser, but also tripling the laser (a much more difficult and sensitive combination) met our model predictions over a wide range of laser

  3. Double pattern EDA solutions for 32nm HP and beyond

    NASA Astrophysics Data System (ADS)

    Bailey, George E.; Tritchkov, Alexander; Park, Jea-Woo; Hong, Le; Wiaux, Vincent; Hendrickx, Eric; Verhaegen, Staf; Xie, Peng; Versluijs, Janko

    2007-03-01

    The fate of optical-based lithography hinges on the ability to deploy viable resolution enhancement techniques (RET). One such solution is double patterning (DP). Like the double-exposure technique, double patterning is a decomposition of the design to relax the pitch that requires dual masks, but unlike double-exposure techniques, double patterning requires an additional develop and etch step, which eliminates the resolution degradation due to the cross-coupling that occurs in the latent images of multiple exposures. This additional etch step is worth the effort for those looking for an optical extension [1]. The theoretical k I for a double-patterning technique of a 32nm half-pitch (HP) design for a 1.35NA 193nm imaging system is 0.44 whereas the k I for a single-exposure technique of this same design would be 0.22 [2], which is sub-resolution. There are other benefits to the DP technique such as the ability to add sub-resolution assist features (SRAF) in the relaxed pitch areas, the reduction of forbidden pitches, and the ability to apply mask biases and OPC without encountering mask constraints. Similarly to AltPSM and SRAF techniques one of the major barriers to widespread deployment of double patterning to random logic circuits is design compliance with split layout synthesis requirements [3]. Successful implementation of DP requires the evolution and adoption of design restrictions by specifically tailored design rules. The deployment of double patterning does spawn a couple of issues that would need addressing before proceeding into a production environment. As with any dual-mask RET application, there are the classical overlay requirements between the two exposure steps and there are the complexities of decomposing the designs to minimize the stitching but to maximize the depth of focus (DoF). In addition, the location of the design stitching would require careful consideration. For example, a stitch in a field region or wider lines is preferred over a

  4. High-power pulsed 976-nm DFB laser diodes

    NASA Astrophysics Data System (ADS)

    Zeller, Wolfgang; Kamp, Martin; Koeth, Johannes; Worschech, Lukas

    2010-04-01

    Distributed feedback (DFB) laser diodes nowadays provide stable single mode emission for many different applications covering a wide wavelength range. The available output power is usually limited because of catastrophical optical mirror damage (COD) caused by the small facet area. For some applications such as trace gas detection output powers of several ten milliwatts are sufficiently high, other applications like distance measurement or sensing in harsh environments however require much higher output power levels. We present a process combining optimizations of the layer structure with a new lateral design of the ridge waveguide which is fully compatible with standard coating and passivation processes. By implementing a large optical cavity with the active layer positioned not in the middle of the waveguide layers but very close to the upper edge, the lasers' farfield angles can be drastically reduced. Furthermore, the travelling light mode can be pushed down into the large optical cavity by continuously decreasing the ridge waveguide width towards both laser facets. The light mode then spreads over a much larger area, thus reducing the surface power density which leads to significantly higher COD thresholds. Laterally coupled DFB lasers based on this concept emitting at wavelengths around 976 nm yield hitherto unachievable COD thresholds of 1.6 W under pulsed operation. The high mode stability during the 50 ns pulses means such lasers are ideally suited for high precision distance measurement or similar tasks.

  5. High-speed stimulated Brillouin scattering spectroscopy at 780 nm

    NASA Astrophysics Data System (ADS)

    Remer, Itay; Bilenca, Alberto

    2016-09-01

    We demonstrate a high-speed stimulated Brillouin scattering (SBS) spectroscopy system that is able to acquire stimulated Brillouin gain point-spectra in water samples and Intralipid tissue phantoms over 2 GHz within 10 ms and 100 ms, respectively, showing a 10-100 fold increase in acquisition rates over current frequency-domain SBS spectrometers. This improvement was accomplished by integrating an ultra-narrowband hot rubidium-85 vapor notch filter in a simplified frequency-domain SBS spectrometer comprising nearly counter-propagating continuous-wave pump-probe light at 780 nm and conventional single-modulation lock-in detection. The optical notch filter significantly suppressed stray pump light, enabling detection of stimulated Brillouin gain spectra with substantially improved acquisition times at adequate signal-to-noise ratios (˜25 dB in water samples and ˜15 dB in tissue phantoms). These results represent an important step towards the use of SBS spectroscopy for high-speed measurements of Brillouin gain resonances in scattering and non-scattering samples.

  6. Electrical control of antiferromagnetic metal up to 15 nm

    NASA Astrophysics Data System (ADS)

    Zhang, PengXiang; Yin, GuFan; Wang, YuYan; Cui, Bin; Pan, Feng; Song, Cheng

    2016-08-01

    Manipulation of antiferromagnetic (AFM) spins by electrical means is on great demand to develop the AFM spintronics with low power consumption. Here we report a reversible electrical control of antiferromagnetic moments of FeMn up to 15 nm, using an ionic liquid to exert a substantial electric-field effect. The manipulation is demonstrated by the modulation of exchange spring in [Co/Pt]/FeMn system, where AFM moments in FeMn pin the magnetization rotation of Co/Pt. By carrier injection or extraction, the magnetic anisotropy of the top layer in FeMn is modulated to influence the whole exchange spring and then passes its influence to the [Co/Pt]/FeMn interface, through a distance up to the length of exchange spring that fully screens electric field. Comparing FeMn to IrMn, despite the opposite dependence of exchange bias on gate voltages, the same correlation between carrier density and exchange spring stiffness is demonstrated. Besides the fundamental significance of modulating the spin structures in metallic AFM via all-electrical fashion, the present finding would advance the development of low-power-consumption AFM spintronics.

  7. 980nm diode laser pump modules operating at high temperature

    NASA Astrophysics Data System (ADS)

    Campbell, Jenna; Semenic, Tadej; Leisher, Paul; Bhunia, Avijit; Mashanovitch, Milan; Renner, Daniel

    2016-03-01

    Existing thermal management technologies for diode laser pumps place a significant load on the size, weight and power consumption of High Power Solid State and Fiber Laser systems, thus making current laser systems very large, heavy, and inefficient in many important practical applications. This problem is being addressed by the team formed by Freedom Photonics and Teledyne Scientific through the development of novel high power laser chip array architectures that can operate with high efficiency when cooled with coolants at temperatures higher than 50 degrees Celsius and also the development of an advanced thermal management system for efficient heat extraction from the laser chip array. This paper will present experimental results for the optical, electrical and thermal characteristics of 980 nm diode laser pump modules operating effectively with liquid coolant at temperatures above 50 degrees Celsius, showing a very small change in performance as the operating temperature increases from 20 to 50 degrees Celsius. These pump modules can achieve output power of many Watts per array lasing element with an operating Wall-Plug-Efficiency (WPE) of >55% at elevated coolant temperatures. The paper will also discuss the technical approach that has enabled this high level of pump module performance and opportunities for further improvement.

  8. Nuclear magnetic resonance imaging with 90-nm resolution.

    PubMed

    Mamin, H J; Poggio, M; Degen, C L; Rugar, D

    2007-05-01

    Magnetic resonance imaging (MRI) is a powerful imaging technique that typically operates on the scale of millimetres to micrometres. Conventional MRI is based on the manipulation of nuclear spins with radio-frequency fields, and the subsequent detection of spins with induction-based techniques. An alternative approach, magnetic resonance force microscopy (MRFM), uses force detection to overcome the sensitivity limitations of conventional MRI. Here, we show that the two-dimensional imaging of nuclear spins can be extended to a spatial resolution better than 100 nm using MRFM. The imaging of 19F nuclei in a patterned CaF(2) test object was enabled by a detection sensitivity of roughly 1,200 nuclear spins at a temperature of 600 mK. To achieve this sensitivity, we developed high-moment magnetic tips that produced field gradients up to 1.4 x 10(6) T m(-1), and implemented a measurement protocol based on force-gradient detection of naturally occurring spin fluctuations. The resulting detection volume was less than 650 zeptolitres. This is 60,000 times smaller than the previous smallest volume for nuclear magnetic resonance microscopy, and demonstrates the feasibility of pushing MRI into the nanoscale regime.

  9. Analysis of wafer heating in 14nm DUV layers

    NASA Astrophysics Data System (ADS)

    Subramany, Lokesh; Chung, Woong Jae; Samudrala, Pavan; Gao, Haiyong; Aung, Nyan; Gomez, Juan Manuel; Minghetti, Blandine; Lee, Shawn

    2016-03-01

    To further shrink the contact and trench dimensions, Negative Tone Development (NTD) has become the de facto process at these layers. The NTD process uses a positive tone resist and an organic solvent-based negative tone developer which leads to improved image contrast, larger process window and smaller Mask Error Enhancement Factor (MEEF)[1]. The NTD masks have high transmission values leading to lens heating and as observed here wafer heating as well. Both lens and wafer heating will contribute to overlay error, however the effects of lens heating can be mitigated by applying lens heating corrections while no such corrections exist for wafer heating yet. Although the magnitude of overlay error due to wafer heating is low relative to lens heating; ever tightening overlay requirements imply that the distortions due to wafer heating will quickly become a significant part of the overlay budget. In this work the effects, analysis and observations of wafer heating on contact and metal layers of the 14nm node are presented. On product wafers it manifests as a difference in the scan up and scan down signatures between layers. An experiment to further understand wafer heating is performed with a test reticle that is used to monitor scanner performance.

  10. Maskless Plasmonic Lithography at 22 nm Resolution

    PubMed Central

    Pan, Liang; Park, Yongshik; Xiong, Yi; Ulin-Avila, Erick; Wang, Yuan; Zeng, Li; Xiong, Shaomin; Rho, Junsuk; Sun, Cheng; Bogy, David B.; Zhang, Xiang

    2011-01-01

    Optical imaging and photolithography promise broad applications in nano-electronics, metrologies, and single-molecule biology. Light diffraction however sets a fundamental limit on optical resolution, and it poses a critical challenge to the down-scaling of nano-scale manufacturing. Surface plasmons have been used to circumvent the diffraction limit as they have shorter wavelengths. However, this approach has a trade-off between resolution and energy efficiency that arises from the substantial momentum mismatch. Here we report a novel multi-stage scheme that is capable of efficiently compressing the optical energy at deep sub-wavelength scales through the progressive coupling of propagating surface plasmons (PSPs) and localized surface plasmons (LSPs). Combining this with airbearing surface technology, we demonstrate a plasmonic lithography with 22 nm half-pitch resolution at scanning speeds up to 10 m/s. This low-cost scheme has the potential of higher throughput than current photolithography, and it opens a new approach towards the next generation semiconductor manufacturing. PMID:22355690

  11. 10{times} reduction imaging at 13.4nm

    SciTech Connect

    Tichenor, D.A.; Kubiak, G.D.; Malinowski, M.E.

    1994-08-01

    A Schwarzschild imaging system has been designed to achieve 0.1 {mu}m resolution in a 0.4 mm diameter field of view when operated at a center wavelength of 13.4 nm. A decentered aperture is located on the convex primary resulting in an unobstructed numerical aperture of 0.08 and a corresponding depth of field of {plus_minus} 1 {mu}m. The Schwarzschild imaging objective is part of a five-reflection system containing the laser plasma source (LPS), condensing optics, turning mirror and reflection mask as shown in Figure 1. Extreme ultraviolet (EUV) radiation is generated by impinging a laser beam onto a copper target. The plasma source is driven by a Lambda Physik PLX 250 KrF excimer laser emitting 0.6 Joule, 20 ns pulses at a 200 Hz maximum repetition rate. Measurements of the source indicate that the full-width-half-maximum diameter is less than 100 {mu}m.

  12. Observations of thunderstorm-related 630 nm airglow depletions

    NASA Astrophysics Data System (ADS)

    Kendall, E. A.; Bhatt, A.

    2015-12-01

    The Midlatitude All-sky imaging Network for Geophysical Observations (MANGO) is an NSF-funded network of 630 nm all-sky imagers in the continental United States. MANGO will be used to observe the generation, propagation, and dissipation of medium and large-scale wave activity in the subauroral, mid and low-latitude thermosphere. This network is actively being deployed and will ultimately consist of nine all-sky imagers. These imagers form a network providing continuous coverage over the western United States, including California, Oregon, Washington, Utah, Arizona and Texas extending south into Mexico. This network sees high levels of both medium and large scale wave activity. Apart from the widely reported northeast to southwest propagating wave fronts resulting from the so called Perkins mechanism, this network observes wave fronts propagating to the west, north and northeast. At least three of these anomalous events have been associated with thunderstorm activity. Imager data has been correlated with both GPS data and data from the AIRS (Atmospheric Infrared Sounder) instrument on board NASA's Earth Observing System Aqua satellite. We will present a comprehensive analysis of these events and discuss the potential thunderstorm source mechanism.

  13. Domain wall motion in sub-100 nm magnetic wire

    NASA Astrophysics Data System (ADS)

    Siddiqui, Saima; Dutta, Sumit; Currivan, Jean Anne; Ross, Caroline; Baldo, Marc

    2015-03-01

    Nonvolatile memory devices such as racetrack memory rely on the manipulation of domain wall (DW) in magnetic nanowires, and scaling of these devices requires an understanding of domain wall behavior as a function of the wire width. Due to the increased importance of edge roughness and magnetostatic interaction, DW pinning increases dramatically as the wire dimensions decrease and stochastic behavior is expected depending on the distribution of pinning sites. We report on the field driven DW statistics in sub-100 nm wide nanowires made from Co films with very small edge roughness. The nanowires were patterned in the form of a set of concentric rings of 10 μm diameter. Two different width nanowires with two different spacings have been studied. The rings were first saturated in plane to produce onion states and then the DWs were translated in the wires using an orthogonal in-plane field. The position of the DWs in the nanowires was determined with magnetic force microscopy. From the positions of the DWs in the nanowires, the strength of the extrinsic pinning sites was identified and they follow two different distributions in two different types of nanowire rings. For the closely spaced wires, magnetostatic interactions led to correlated movement of DWs in neighboring wires. The implications of DW pinning and interaction in nanoscale DW devices will be discussed.

  14. Effects of 810 nm laser on mouse primary cortical neurons

    NASA Astrophysics Data System (ADS)

    Kharkwal, Gitika B.; Sharma, Sulbha K.; Huang, Ying-Ying; De Taboada, Luis; McCarthy, Thomas; Hamblin, Michael R.

    2011-03-01

    In the past four decades numerous studies have reported the efficacy of low level light (laser) therapy (LLLT) as a treatment for diverse diseases and injuries. Recent studies have shown that LLLT can biomodulate processes in the central nervous system and has been extensively studied as a stroke treatment. However there is still a lack of knowledge on the effects of LLLT at the cellular level in neurons. The present study aimed to study the effect of 810 nm laser on several cellular processes in primary cortical neurons cultured from mouse embryonic brains. Neurons were irradiated with light dose of 0.03, 0.3, 3, 10 and 30 J/cm2 and intracellular levels of reactive oxygen species, nitric oxide and calcium were measured. The changes in mitochondrial function in response to light were studied in terms of adenosine triphosphate (ATP) and mitochondrial membrane potential (MMP). Light induced a significant increase in calcium, ATP and MMP at lower fluences and a decrease at higher fluence. ROS was induced significantly by light at all light doses. Nitric oxide levels also showed an increase on treatment with light. The results of the present study suggest that LLLT at lower fluences is capable of inducing mediators of cell signaling process which in turn may be responsible for the biomodulatory effects of the low level laser. At higher fluences beneficial mediators are reduced but potentially harmful mediators are increased thus offering an explanation for the biphasic dose response.

  15. A stable 657nm laser for a Ca atom interferometer

    NASA Astrophysics Data System (ADS)

    Neyenhuis, Brian; Erickson, Christopher; Tang, Rebecca; Doermann, Greg; van Zijll, Marshall; Durfee, Dallin

    2006-05-01

    We will present an extremely stable laser to be used in an atom interferometer. A 657nm grating-stabilized diode laser is locked to a high-finesse cavity using the Pound-Drever-Hall method. Utilizing a feedback circuit with a bandwidth of 5 MHz we see a laser linewidth less than one kHz. In addition to a relatively high bandwidth, our circuit design allows for mode-hop-free scanning over a large range. We are also working on several improvements which should further reduce our linewidth; we are improving passive mechanical and thermal stability of the laser and the optical cavity and plan to change to a higher finesse cavity, we have designed and are testing a more stable current driver based on an updated Hall-Libbrecht design, and we calculating an optimized multiple-input feedback transfer function for our system. We will also present the measurement of the resonances of our optical cavity relative to the Ca intercombination line using a high-temperature vapor cell.

  16. Patterning challenges in the sub-10 nm era

    NASA Astrophysics Data System (ADS)

    Preil, Moshe E.

    2016-03-01

    Historically, progress in lithography has been driven by steady advances in exposure tool and optical technology; shorter wavelength, higher numerical aperture (NA) and resolution enhancement techniques to drive the k1 factor as close as possible to the physical limit. Over the past decade, however, the pace of progress has been gated more by patterning - what we do after the resist image is printed - than by higher resolution imaging. The emphasis on patterning rather than just printing has created new pressures in many parts of the overall process, beginning with the design itself. The breakdown of lithographic error budgets into CD and OL tolerances has given way to total edge placement error (EPE) budgets where CD, OL and edge roughness, as well as film and etch variations, must all be controlled to meet the required tolerances. Contact hole and cut mask placement have likewise been tightened to single digit EPE budgets. Collaborative research between technology specialists in multiple areas, such as metrology, etch, process control and simulation, will all be required to deliver these patterning solutions for some years to come. This paper will describe some of these challenges in more detail, and suggest directions for future research to keep optical lithography relevant even below the 10 nm node.

  17. Technique for cellular microsurgery using the 193-nm excimer laser.

    PubMed

    Palanker, D; Ohad, S; Lewis, A; Simon, A; Shenkar, J; Penchas, S; Laufer, N

    1991-01-01

    A new cell surgery technique has been developed to produce well-defined alterations in cells and tissue without detectable heating and/or other structural damage in the surroundings. The technique involves the use of an argon fluoride excimer laser, in the deep ultraviolet (UV) region of the spectrum at 193 nm, which is guided through a glass pipette filled with a positive air pressure. To demonstrate the method, holes were drilled in the zona pellucida of mouse oocytes. The diameter of the drilled hole was determined by the pipette tip size, and its depth by an energy emitted per pulse and number of pulses. Scanning electron microscopy of the drilled mouse oocytes showed uniform, round, well-circumscribed holes with sharp edges. Oocytes that had their zona pellucida drilled with this new method fertilized in vitro and developed to the blastocyst stage in a rate similar to that of control group. These results demonstrate the nonperturbing nature of this cold laser microsurgical procedure. In addition to the extension of our results for clinical in vitro fertilization purposes, such as enhancement of fertilization and embryo biopsy, there are wide-ranging possible uses of our method in fundamental and applied investigations that require submicron accuracy in cellular alteration.

  18. Enabling 22-nm logic node with advanced RET solutions

    NASA Astrophysics Data System (ADS)

    Farys, V.; Depre, L.; Finders, J.; Arnoux, V.; Trouiller, Y.; Liu, H. Y.; Yesilada, E.; Zeggaoui, N.; Alleaume, C.

    2011-04-01

    The 22-nm technology node presents a real breakthrough compared to previous nodes in the way that state of the art scanner will be limited to a numerical aperture of 1.35. Thus we cannot "simply" apply a shrink factor from the previous node, and tradeoffs have to be found between Design Rules, Process integration and RET solutions in order to maintain the 50% density gain imposed by the Moore's law. One of the most challenging parts to enable the node is the ability to pattern Back-End Holes and Metal layers with sufficient process window. It is clearly established that early process for these layers will be performed by double patterning technique coupled with advanced OPC solutions. In this paper we propose a cross comparison between possible double patterning solutions: Pitch Splitting (PS) and Sidewall Image Transfer (SIT) and their implication on design rules and CD Uniformity. Advanced OPC solutions such as Model Based SRAF and Source Mask Optimization will also be investigated in order to ensure good process control. This work is a part of the Solid's JDP between ST, ASML and Brion in the framework of Nano2012 sponsored by the French government.

  19. Complex kinetics of a Landolt-type reaction: the later phase of the thiosulfate-iodate reaction.

    PubMed

    Varga, Dénes; Nagypál, István; Horváth, Attila K

    2010-05-13

    The thiosulfate-iodate reaction has been studied spectrophotometrically in slightly acidic medium at 25.0 +/- 0.1 degrees C in acetate/acetic acid buffer by monitoring the absorbance at 468 nm at the isosbestic point of iodine-triiodide ion system. The formation of iodine after the Landolt time follows a rather complex kinetic behavior depending on the pH and on the concentration of the reactants as well. It is shown that the key intermediate of the reaction is I(2)O(2), its equilibrium formation from the well-known Dushman reaction along with their further reactions followed by subsequent reactions of HOI, HIO(2), S(2)O(3)OH(-), and S(2)O(3)I(-) adequately accounts for all the experimentally measured characteristics of the kinetic curves. A 19-step kinetic model is proposed and discussed with 13 fitted and 7 fixed parameters in detail.

  20. Hydrocarbon-free resonance transition 795-nm rubidium laser

    SciTech Connect

    Wu, S Q; Soules, T F; Page, R H; Mitchell, S C; Kanz, V K; Beach, R J

    2008-01-09

    An optical resonance transition rubidium laser (5{sup 2}P{sub 1/2} {yields} 5{sup 2}S{sub 1/2}) is demonstrated with a hydrocarbon-free buffer gas. Prior demonstrations of alkali resonance transition lasers have used ethane as either the buffer gas or a buffer gas component to promote rapid fine-structure mixing. However, our experience suggests that the alkali vapor reacts with the ethane producing carbon as one of the reaction products. This degrades long term laser reliability. Our recent experimental results with a 'clean' helium-only buffer gas system pumped by a Ti:sapphire laser demonstrate all the advantages of the original alkali laser system, but without the reliability issues associated with the use of ethane.

  1. Strain relaxation in nm-thick Cu and Cu-alloy films bonded to a rigid substrate

    NASA Astrophysics Data System (ADS)

    Herrmann, Ashley Ann Elizabeth

    In the wide scope of modern technology, nm-thick metallic films are increasingly used as lubrication layers, optical coatings, plating seeds, diffusion barriers, adhesion layers, metal contacts, reaction catalyzers, etc. A prominent example is the use of nm-thick Cu films as electroplating seed layers in the manufacturing of integrated circuits (ICs). These high density circuits are linked by on-chip copper interconnects, which are manufactured by filling Cu into narrow trenches by electroplating. The Cu fill by electroplating requires a thin Cu seed deposited onto high-aspect-ratio trenches. In modern ICs, these trenches are approaching 10 nm or less in width, and the seed layers less than 1 nm in thickness. Since nm-thick Cu seed layers are prone to agglomeration or delamination, achieving uniform, stable and highly-conductive ultra-thin seeds has become a major manufacturing challenge. A fundamental understanding of the strain behavior and thermal stability of nm-thick metal films adhered to a rigid substrate is thus critically needed. In this study, we focus on understanding the deformation modes of nm-thick Cu and Cu-alloy films bonded to a rigid Si substrate and under compressive stress. The strengthening of Cu films through alloying is also studied. In-situ transport measurements are used to monitor the deformation of such films as they are heated from room temperature to 400 °C. Ex-situ AFM is then used to help characterize the mode of strain relaxation. The relaxation modes are known to be sensitive to the wetting and adhesive properties of the film-substrate interface. We use four different liners (Ta, Ru, Mo and Co), interposed between the film and substrate to provide a wide range of interfacial properties to study their effect on the film's thermal stability. Our measurements indicate that when the film/liner interfacial energy is low, grain growth is the dominant relaxation mechanism. As the interface energy increases, grain growth is suppressed, and

  2. [Cutaneous adverse drug reactions].

    PubMed

    Lebrun-Vignes, B; Valeyrie-Allanore, L

    2015-04-01

    Cutaneous adverse drug reactions (CADR) represent a heterogeneous field including various clinical patterns without specific features suggesting drug causality. Exanthematous eruptions, urticaria and vasculitis are the most common forms of CADR. Fixed eruption is uncommon in western countries. Serious reactions (fatal outcome, sequelae) represent 2% of CADR: bullous reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis), DRESS (drug reaction with eosinophilia and systemic symptoms or drug-induced hypersensitivity syndrome) and acute generalized exanthematous pustulosis (AGEP). These forms must be quickly diagnosed to guide their management. The main risk factors are immunosuppression, autoimmunity and some HLA alleles in bullous reactions and DRESS. Most systemic drugs may induce cutaneous adverse reactions, especially antibiotics, anticonvulsivants, antineoplastic drugs, non-steroidal anti-inflammatory drugs, allopurinol and contrast media. Pathogenesis includes immediate or delayed immunologic mechanism, usually not related to dose, and pharmacologic/toxic mechanism, commonly dose-dependent or time-dependent. In case of immunologic mechanism, allergologic exploration is possible to clarify drug causality, with a variable sensitivity according to the drug and to the CADR type. It includes epicutaneous patch testing, prick test and intradermal test. However, no in vivo or in vitro test can confirm the drug causality. To determine the cause of the eruption, a logical approach based on clinical characteristics, chronologic factors and elimination of differential diagnosis is required, completed with a literature search. A reporting to pharmacovigilance network is essential in case of a serious CADR whatever the suspected drug and in any case if the involved drug is a newly marketed one or unusually related to cutaneous reactions.

  3. Photolysis of Pure Solid O3 and O2 Films at 193nm

    NASA Technical Reports Server (NTRS)

    Raut, U.; Loeffler, M. J.; Fama, M.; Baragiola, R. A.

    2011-01-01

    We studied quantitatively the photochemistry of solid O3 and O2 films at 193 nm and 22 K with infrared spectroscopy and microgravimetry. Photolysis of pure ozone destroyed O3, but a small amount of ozone remained in the film at high fluence. Photolysis of pure O2 produced O3 in an amount that increased with photon fluence to a stationary level. For both O2 and O3 films, the O3:O2 ratio at large fluences is ?0.07, about two orders of magnitude larger than those obtained in gas phase photolysis. This enhancement is attributed to the increased photodissociation of O2 due to photoabsorption by O2 dimers, a process significant at solid-state densities. We obtain initial quantum yield for ozone synthesis from solid oxygen, phi (O3) = 0.24 0.06, and quantum yields for destruction of O3 and O2 in their parent solids, phi(-O3) = 1.0 0.2 and phi(-O2) = 0.36 0.1. Combined with known photoabsorption cross sections, we estimate probabilities for geminate recombination of 0.5 0.1 for O3 fragments and 0.88 0.03 for oxygen atoms from O2 dissociation. Using a single parameter kinetic model, we deduce the ratio of reaction cross sections for an O atom with O2 vs. O3 to be 0.1 0.2. The general good agreement of the model with the data suggests the validity of the central assumption of efficient energy and spin relaxation of photofragments in the solid prior to their reactions with other species.

  4. A compact dual-wavelength Nd:LuVO4 laser with adjustable power-ratio between 1064 nm and 1342 nm lines by controlling polarization dependent loss

    NASA Astrophysics Data System (ADS)

    Qi, Yaoyao; Yu, Haijuan; Zhang, Jingyuan; Zhang, Ling; He, Chaojian; Lin, Xuechun

    2017-01-01

    We demonstrate a compact dual-wavelength operation of Nd:LuVO4 laser with a power-ratio adjustable between 1064 nm and 1342 nm lines in a compound cavity configuration. The output power at two wavelengths of the laser indicates that it depends not only on pumping-power and but also on the controllable polarization loss in the cavity. Also, the power-ratio, defined as ratio between the output power at 1064 nm and that at 1342 nm, can be adjusted from 0 to 8 or higher accurately by rotating a quarter-wave plate (QWP) in the cavity.

  5. Etching of 42-nm and 32-nm half-pitch features patterned using step and Flash® imprint lithography

    NASA Astrophysics Data System (ADS)

    Brooks, Cynthia B.; LaBrake, Dwayne L.; Khusnatdinov, Niyaz

    2008-03-01

    In this work, the authors demonstrate the suitability of Step and Flash® Imprint Lithography (S-FIL®) materials as a mask for patterning 42 nm and 32 nm half pitch features into a hardmask material. We present a zero etch-bias process with good silicon oxide to imprint resist selectivity and excellent line-width roughness (LWR) control. We demonstrate the required etch processes and mean value and uniformity of the residual layer thickness (RLT) necessary to maintain cross wafer CD uniformity for 42 nm and 32 nm half pitch dense lines. Finally, the authors present a mechanism for targeting the critical dimension by control of the imprint resist volume.

  6. Wavelength Dependence in the Analysis of Carbon Content in Coal by Nanosecond 266 nm and 1064 nm Laser Induced Breakdown Spectroscopy

    NASA Astrophysics Data System (ADS)

    Li, Xiongwei; Wang, Zhe; Fu, Yangting; Li, Zheng; Ni, Weidou

    2015-08-01

    The wavelength dependence of laser induced breakdown spectroscopy (LIBS) in the analysis of the carbon contents of coal was studied using 266 nm and 1064 nm laser radiations. Compared with the 1064 nm wavelength laser ablation, the 266 nm wavelength laser ablation has less thermal effects, resulting in a better crater morphology on the coal pellets. Besides, the 266 nm wavelength laser ablation also provides better laser-sample coupling and less plasma shielding, resulting in a higher carbon line intensity and better signal reproducibility. The carbon contents in the bituminous coal samples have better linearity with the line intensities of atomic carbon measured by the 266 nm wavelength than those measured by the 1064 nm wavelength. The partial least square (PLS) model was established for the quantitative analysis of the carbon content in coal samples by LIBS. The results show that both of the 266 nm and 1064 nm wavelengths are capable of achieving good performance for the quantitative analysis of carbon content in coal using the PLS method. supported by National Natural Science Foundation of China (No. 51276100) and National Basic Research Program of China (973 Program) (No. 2013CB228501)

  7. Development of fluoropolymer for 193nm immersion lithography

    NASA Astrophysics Data System (ADS)

    Shirota, Naoko; Takebe, Yoko; Sasaki, Takashi; Yokokoji, Osamu; Toriumi, Minoru; Masuhara, Hiroshi

    2006-03-01

    We had already developed several series of fluoropolymers, FPRs and FUGUs, having a partially fluorinated monocyclic structure and having acidic hydroxyl group, which acts as dissolution unit into alkaline solution. Then we have optimized these polymers for top-coat as the developer-soluble type in the 193nm immersion lithography. However the hydrophobicity of these polymers were a little poor due to its hydroxyl group. So we thought that the introduction of water repellent moiety into the these polymers structure is effective to improve the their hydrophobicity though the increase of water repellent unit in the polymer leads to lower dissolution rate in developer. To introduce as much as possible of hydrophobicity unit, we selected FUGU as platform, which has larger dissolution rate in developer than that of FPRs, We copolymerized FUGU with higher water-repellent component and obtained three copolymers, FUGU-CoA, FUGU-CoB, and FUGU-CoC. In this paper, we described characteristics and evaluation of these polymers. Most of these polymer showed an improvement of hydrophobicity, in particular FUGU-CoB had excellent hydrophobicity due to introduction bulky containing-fluorine group. In this study, we also investigated the interaction between the water and various polymers by using QCM method. The difference between FUGU and water repellent polymers for swelling behavior to water became clear by analysis of diffusion coefficient. We found that our new co-polymers have excellent diffusion coefficient than FUGU which was confirmed by QCM method used to evaluate water permeability and water diffusion in the materials.

  8. Ion Exclusion by Sub 2-nm Carbon Nanotube Pores

    SciTech Connect

    Fornasiero, F; Park, H G; Holt, J K; Stadermann, M; Grigoropoulos, C P; Noy, A; Bakajin, O

    2008-04-09

    Carbon nanotubes offer an outstanding platform for studying molecular transport at nanoscale, and have become promising materials for nanofluidics and membrane technology due to their unique combination of physical, chemical, mechanical, and electronic properties. In particular, both simulations and experiments have proved that fluid flow through carbon nanotubes of nanometer size diameter is exceptionally fast compared to what continuum hydrodynamic theories would predict when applied on this length scale, and also, compared to conventional membranes with pores of similar size, such as zeolites. For a variety of applications such as separation technology, molecular sensing, drug delivery, and biomimetics, selectivity is required together with fast flow. In particular, for water desalination, coupling the enhancement of the water flux with selective ion transport could drastically reduce the cost of brackish and seawater desalting. In this work, we study the ion selectivity of membranes made of aligned double-walled carbon nanotubes with sub-2 nm diameter. Negatively charged groups are introduced at the opening of the carbon nanotubes by oxygen plasma treatment. Reverse osmosis experiments coupled with capillary electrophoresis analysis of permeate and feed show significant anion and cation rejection. Ion exclusion declines by increasing ionic strength (concentration) of the feed and by lowering solution pH; also, the highest rejection is observed for the A{sub m}{sup Z{sub A}} C{sub n}{sup Z{sub C}} salts (A=anion, C=cation, z= valence) with the greatest Z{sub A}/Z{sub C} ratio. Our results strongly support a Donnan-type rejection mechanism, dominated by electrostatic interactions between fixed membrane charges and mobile ions, while steric and hydrodynamic effects appear to be less important. Comparison with commercial nanofiltration membranes for water softening reveals that our carbon nanotube membranes provides far superior water fluxes for similar ion

  9. Raman spectroscopic identification of arsenate minerals in situ at outcrops with handheld (532 nm, 785 nm) instruments

    NASA Astrophysics Data System (ADS)

    Culka, Adam; Kindlová, Helena; Drahota, Petr; Jehlička, Jan

    2016-02-01

    Minerals are traditionally identified under field conditions by experienced mineralogists observing the basic physical properties of the samples. Under laboratory conditions, a plethora of techniques are commonly used for identification of the geological phases based on their structural and spectroscopic parameters. In this area, Raman spectrometry has become a useful tool to complement the more widely applied XRD. Today, however, there is an acute need for a technique for unambiguous in situ identification of minerals, within the geological as well as planetary/exobiology realms. With the potential for miniaturization, Raman spectroscopy can be viewed as a practical technique to achieve these goals. Here, for the first time, the successful application of handheld Raman spectrometers is demonstrated to detect and discriminate arsenic phases in the form of earthy aggregates. The Raman spectroscopic analyses of arsenate minerals were performed in situ using two handheld instruments, using 532 and 785 nm excitation. Bukovskýite, kaňkite, parascorodite, and scorodite were identified from Kaňk near Kutná Hora, CZE; kaňkite, scorodite, and zýkaite were identified at the Lehnschafter gallery in an old silver mine at Mikulov near Teplice, Bohemian Massif, CZE.

  10. Parametric Study of Up-Conversion Efficiency in Er-Doped Lanthanide Hosts Under 780 nm/980 nm Excitation Wavelengths

    NASA Astrophysics Data System (ADS)

    Samir, E.; Shehata, N.; Aldacher, M.; Kandas, I.

    2016-06-01

    Up-conversion is a process of converting low energy light photons to higher energy ones, which can be extensively used in many applications. This paper presents a detailed parametric study of the up-conversion process under different wavelength excitations—780 nm and 980 nm—showing the optical conversion mechanisms that affect the emitted light quantum yield efficiencies. The studied material is erbium-doped β-NaYF4 material, which is one of the most recently studied materials due to its low phonon energy. The studied simulation considers most processes and possible transitions that can take place between Er3+ ions. Einstein coefficients, which are the main parameters that are responsible for the transitions probabilities, are discussed in detail using Judd-Ofelt analysis. In addition, the effect of changing some parametric values is discussed, showing their optimum values that could improve the quantum yield efficiency. This model is very promising, and generic, and can be applied for any host material under any excitation wavelengths by varying the material-dependent parameters.

  11. Visible Light Mediated Photoredox Catalytic Arylation Reactions.

    PubMed

    Ghosh, Indrajit; Marzo, Leyre; Das, Amrita; Shaikh, Rizwan; König, Burkhard

    2016-08-16

    anion of the organic dye perylenediimide is excited by a second photon allowing the one electron reduction of acceptor substituted aryl chlorides. The radical anion of the aryl halide fragments under the loss of a halide ion and the aryl radical undergoes C-H arylation with biologically important pyrrole derivatives or adds to a double bond. Rhodamine 6G as an organic photocatalyst allows an even higher degree of control of the reaction. The dye is photoreduced in the presence of an amine donor under irradiation with green light (e.g., 530 nm), yielding its radical anion, which is a mild reducing reagent. The hypsochromic shift of the absorption of the rhodamine 6G radical anion toward blue region of the visible light spectrum allows its selective excitation using blue light (e.g., 455 nm). The excited radical anion is highly reducing and able to activate even bromoanisole for C-H arylation reactions, although only in moderate yield. Photoredox catalytic C-H arylation reactions are valuable alternatives to metal catalyzed reactions. They have an excellent functional group tolerance, could potentially avoid metal containing catalysts, and use visible light as a traceless reagent for the activation of arylating reagents.

  12. Reaction/Momentum Wheel

    NASA Technical Reports Server (NTRS)

    1997-01-01

    CTA Space Systems, Inc. has been licensed to sell commercially a reaction/momentum wheel originally developed for NASA's scientific satellites. NASA originally identified a need for the wheel in its Small Explorer program. The Submillimeter Wave Astronomy Satellite required extremely low jitter and a reaction/momentum wheel with a torque greater than any comparably sized commercially available wheel to keep the instrument pointed at celestial objects to a high degree of precision. After development, a market assessment by Research Triangle Institute was completed, showing commercial potential for the flywheel technology. A license was granted to CTA in the fall of 1996. The company currently uses the technology in its complete spacecraft fabrication services and has built over 10 reaction/momentum wheels for commercial, scientific, and military customers.

  13. Laser-Initiated Free Radical Chain Reactions: Synthesis Of Hydroperoxides

    NASA Astrophysics Data System (ADS)

    Bray, R. G.; Chou, M. S.

    1984-05-01

    We have investigated the advantages of using laser-initiation for the synthesis of cumenehydroperoxide and t-butylhydroperoxide. Laser-initiation significantly improves the oxidation rates of cumene in the liquid phase and iso-butane in the vapor phase (using HBr promoters) with moderate photoefficiencies (418 and 490 respectively). The primary effect of laser-initiation is to reduce the induction period of the reaction. For the oxidation of cumene the beneficial effect of laser initiation is strongly dependent on laser wavelength, alternately enhancing (at 351 nm) or inhibiting (at 249 nm) the oxidation rate. For isobutane oxidation, laser-initiation also minimizes the HBr depletion rate relative to oxidation rate.

  14. Velocity pump reaction turbine

    DOEpatents

    House, Palmer A.

    1984-01-01

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

  15. Velocity pump reaction turbine

    DOEpatents

    House, Palmer A.

    1982-01-01

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

  16. Velocity pump reaction turbine

    SciTech Connect

    House, P.A.

    1984-02-07

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

  17. Velocity pump reaction turbine

    SciTech Connect

    House, P.A.

    1982-06-01

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an interrotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal application

  18. Velocity pump reaction turbine

    DOEpatents

    House, P.A.

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

  19. Experimental Study of Closed System in the Chlorine Dioxide-Iodide-Sulfuric Acid Reaction by UV-Vis Spectrophotometric Method

    PubMed Central

    Li, Na; Shi, Laishun; Wang, Xiaomei; Guo, Fang; Yan, Chunying

    2011-01-01

    The mole ratio r(r = [I−]0/[ClO2]0) has great influence on ClO2-I−-H2SO4 closed reaction system. By changing the initiate concentration of potassium iodide, the curve of absorbance along with the reaction time was obtained at 350 nm and 297 nm for triiodide ion, and 460 nm for iodine. The changing point of the absorbance curve's shape locates at r = 6.00. For the reaction of ClO2-I− in the absence of H2SO4, the curve of absorbance along with the reaction time can be obtained at 350 nm for triiodide ion, 460 nm for iodine. The mole ratio r is equal to 1.00 is the changing point of the curve's shape no matter at which wavelength to determine the reaction. For the reaction of ClO2-I−-H+ in different pH buffer solution, the curve of absorbance along with the reaction time was recorded at 460 nm for iodine. When r is greater than 1.00, the transition point of the curve's shape locates at pH 2.0, which is also the point of producing chlorite or chloride for chlorine dioxide at different pH. When r is less than 1.00, the transition point locates at pH 7.0. PMID:21808646

  20. Decomposition of Iodinated Pharmaceuticals by UV-254 nm-assisted Advanced Oxidation Processes.

    PubMed

    Duan, Xiaodi; He, Xuexiang; Wang, Dong; Mezyk, Stephen P; Otto, Shauna C; Marfil-Vega, Ruth; Mills, Marc A; Dionysiou, Dionysios D

    2017-02-05

    Iodinated pharmaceuticals, thyroxine (a thyroid hormone) and diatrizoate (an iodinated X-ray contrast medium), are among the most prescribed active pharmaceutical ingredients. Both of them have been reported to potentially disrupt thyroid homeostasis even at very low concentrations. In this study, UV-254 nm-based photolysis and photochemical processes, i.e., UV only, UV/H2O2, and UV/S2O8(2-), were evaluated for the destruction of these two pharmaceuticals. Approximately 40% of 0.5μM thyroxine or diatrizoate was degraded through direct photolysis at UV fluence of 160mJcm(-2), probably resulting from the photosensitive cleavage of C-I bonds. While the addition of H2O2 only accelerated the degradation efficiency to a low degree, the destruction rates of both chemicals were significantly enhanced in the UV/S2O8(2-) system, suggesting the potential vulnerability of the iodinated chemicals toward UV/S2O8(2-) treatment. Such efficient destruction also occurred in the presence of radical scavengers when biologically treated wastewater samples were used as reaction matrices. The effects of initial oxidant concentrations, solution pH, as well as the presence of natural organic matter (humic acid or fulvic acid) and alkalinity were also investigated in this study. These results provide insights for the removal of iodinated pharmaceuticals in water and/or wastewater using UV-based photochemical processes.

  1. Interactions of human blood and tissue cell types with 95-nm-high nanotopography.

    PubMed

    Dalby, Matthew J; Marshall, George E; Johnstone, Heather J H; Affrossman, Stanley; Riehle, Mathis O

    2002-03-01

    Two of the major concerns for tissue engineering materials are inflammatory responses from blood cells and fibrous encapsulation by the body in order to shield the implant from blood reaction. A further hurdle is that of vascularization. In order to develop new tissues, or to repair parts of the vascular system, nutrients need to be carried to the basal cell layers. If a material promotes tissue formation, but not vascularization, necrosis will be observed as multilayered cells develop. In this paper, polymer demixed island topography with a 95-nm Z axis was tested using human mononuclear blood cells, platelets, fibroblasts, and endothelial cells. The results showed no difference in blood response between the islands and the flat controls, suggesting that in vivo there would be negligible immunological difference. Fibroblasts reacted by changing morphology into a rounded shape with thick processes and poorly developed cytoskeleton. Retardation of fibroblast growth may be an advantageous, as it is this cell type that forms the fibrous capsule, preventing growth of the required tissue type. Finally, endothelial cells were seen to form arcuate, or curved, morphologies in response to the islands. This is the normal, in vivo, morphology for vascular endothelium. This result suggests that the nano-features are promoting a more phenotypically correct morphology.

  2. The stability of allyl radicals following the photodissociation of allyl iodide at 193 nm.

    SciTech Connect

    Fan, H.; Pratt, S. T.; Chemistry

    2006-01-01

    The photodissociation of allyl iodide (C{sub 3}H{sub 5}I) at 193 nm was investigated by using a combination of vacuum-ultraviolet photoionization of the allyl radical, resonant multiphoton ionization of the iodine atoms, and velocity map imaging. The data provide insight into the primary C-I bond fission process and into the dissociative ionization of the allyl radical to produce C{sub 3}H{sup 3+}. The experimental results are consistent with the earlier results of Szpunar et al. [J. Chem. Phys. 119, 5078 (2003)], in that some allyl radicals with internal energies higher than the secondary dissociation barrier are found to be stable. This stability results from the partitioning of available energy between the rotational and vibrational degrees of freedom of the radical, the effects of a centrifugal barrier along the reaction coordinate, and the effects of the kinetic shift in the secondary dissociation of the allyl radical. The present results suggest that the primary dissociation of allyl iodide to allyl radicals plus I*({sup 2}P{sub 1/2}) is more important than previously suspected.

  3. Product channels in the 193-nm photodissociation of HCNO (fulminic acid)

    NASA Astrophysics Data System (ADS)

    Feng, Wenhui; Hershberger, John F.

    2016-06-01

    IR diode laser spectroscopy was used to detect the products of HCNO (fulminic acid) photolysis at 193 nm. Six product channels are energetically possible at this photolysis wavelength: O + HCN, H + NCO/CNO, CN + OH, CO + NH, NO + CH and HNCO. In some experiments, isotopically labeled 15N18O, C2D6 or C6H12 reagents were included into the photolysis mixture in order to suppress and/or redirect possible secondary reactions. HCN, OC18O, 15N15NO, CO, DCN and HNCO molecules were detected upon laser photolysis of HCNO/reagents/buffer gas mixtures. Analysis of the yields of product molecules leads to the following photolysis quantum yields: ϕ1a (O + HCN) = 0.38 ± 0.04, ϕ1b (H + (NCO)) = 0.07 ± 0.02, ϕ1c (CN + OH) = 0.24 ± 0.03, ϕ1d (CO + NH(a1Δ)) < 0.22 ± 0.1, ϕ1e (HNCO) = 0.02 ± 0.01 and ϕ1f (CH + NO) = 0.21 ± 0.1, respectively.

  4. Time-resolved hydrino continuum transitions with cutoffs at 22.8 nm and 10.1 nm

    NASA Astrophysics Data System (ADS)

    Mills, R. L.; Lu, Y.

    2011-09-01

    Spectra of low energy, high current pinch discharges in pure hydrogen, oxygen, nitrogen, and helium were recorded in the EUV region, and continuum radiation was only observed from hydrogen [www.blacklightpower.com/pdf/GEN3_Harvard.pdf; Int. J. Hydrogen Energy 35, 8446 (2010); Cent. Eur. J. Phys. 8, 318 (2010)]. The continuum radiation bands at 10.1 and 22.8 nm and going to longer wavelengths for theoretically predicted transitions of hydrogen to lower-energy, so called "hydrino" states, was observed first at blacklight power, Inc. (BLP) and reproduced at the Harvard center for astrophysics (CfA). Considering the low energy of 5.2 J per pulse, the observed radiation in the energy range of about 120 eV to 40 eV and reference experiments, no conventional explanation was found to be plausible, including electrode metal emission, Bremsstrahlung radiation, ion recombination, molecular or molecular ion band radiation, and instrument artifacts involving radicals and energetic ions reacting at the CCD and H2 re-radiation at the detector chamber. To further study these continuum bands assigned to hydrinos, time resolved spectra were performed that showed a unique delay of the continuum radiation of about 0.1 μs and a duration of < 2 μs following the high-voltage pulse consistent with the mechanism of recombination to form the optimal high-density atomic hydrogen in the pinch that permits the H-H interactions to cause the hydrino transitions and corresponding emission.

  5. 75 FR 66345 - Proposed Amendment of Class E Airspace; Taos, NM

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-28

    ... action proposes to amend Class E airspace at Taos, NM. Decommissioning of the Ski non-directional beacon..., Taos, NM. Airspace reconfiguration is necessary due to the decommissioning of the Ski NDB and...

  6. Sub-10 nm lateral spatial resolution in scanning capacitance microscopy achieved with solid platinum probes

    NASA Astrophysics Data System (ADS)

    Bussmann, E.; Williams, C. C.

    2004-02-01

    Sub-10 nm resolution can be obtained in scanning capacitance microscopy (SCM) if the probe tip is approximately of the same size. Such resolution is observed, although infrequently, with present commercially available probes. To acquire routine sub-10 nm resolution, a solid Pt metal probe has been developed with a sub-10 nm tip radius. The probe is demonstrated by SCM imaging on a cross-sectioned 70 nm gatelength field-effect transistor (FET), a shallow implant (n+/p, 24 nm junction depth), and an epitaxial staircase (p, ˜75 nm steps). Sub-10 nm resolution is demonstrated on the FET device over the abrupt meeting between a silicon-on-insulator oxide layer and a neighboring Si region. Comparable resolution is observed on the implant structure, and quantitative SCM dopant profiling is performed on it with sub-10 nm accuracy. Finally, the epitaxial staircase structure is quantitatively profiled demonstrating the accuracy obtained in quantitative profiling with the tips.

  7. Preliminary report: comparison of 980-nm, 808-nm diode laser enhanced with indocyanine green to the Nd:YAG laser applied to equine respiratory tissue

    NASA Astrophysics Data System (ADS)

    Tate, Lloyd P.; Blikslager, Anthony T.; Campbell, Nigel B.

    2001-05-01

    The Neodynium: Yttrium Aluminum Garnet (Nd:YAG) laser has been the mainstay of performing upper respiratory laser surgery in the equine since 1984. The 808-nm diode laser has also been applied transendoscopically as well as the 980-nm diode laser over recent years. It has been shown that Indocyanine Green (ICG) enhances the performance of the 808- nm laser because it is absorbed at 810 nm of light. The 808- nm laser's tissue interaction combined with ICG is equivalent to or greater than the Nd:YAG laser's cutting ability. The 980-nm diode laser performance was similar to that of the Nd:YAG as determined by the parameters of this study. This study compared the depths and widths of penetration achieved with the 808-nm diode laser after intravenous injection of ICG on equine respiratory tissue. It also compared depths and widths of penetration achieved by the non-contact application of the 980-nm diode laser delivering the same energy of 200 joules. The depths and widths of penetration of both diode lasers were compared to themselves and to the Nd:YAG laser with all factors remaining constant.

  8. Investigation of the Low Power Stage of an 1178 nm Raman System

    DTIC Science & Technology

    2013-12-23

    the 1069 and 1178 nm signals enter the system through a common WDM upstream from the ytterbium amplifier has been described in detail previously15...1178 nm is injected into the laser downstream from the ytterbium doped amplifier. In addition, a 1069/1121/1178 (3 wavelength) WDM is inserted on the...downstream side of the ytterbium doped amplifier to remove any residual 1121 nm propagating upstream that would favorably compete with the 1069 nm

  9. Reaction product imaging

    SciTech Connect

    Chandler, D.W.

    1993-12-01

    Over the past few years the author has investigated the photochemistry of small molecules using the photofragment imaging technique. Bond energies, spectroscopy of radicals, dissociation dynamics and branching ratios are examples of information obtained by this technique. Along with extending the technique to the study of bimolecular reactions, efforts to make the technique as quantitative as possible have been the focus of the research effort. To this end, the author has measured the bond energy of the C-H bond in acetylene, branching ratios in the dissociation of HI, the energetics of CH{sub 3}Br, CD{sub 3}Br, C{sub 2}H{sub 5}Br and C{sub 2}H{sub 5}OBr dissociation, and the alignment of the CD{sub 3} fragment from CD{sub 3}I photolysis. In an effort to extend the technique to bimolecular reactions the author has studied the reaction of H with HI and the isotopic exchange reaction between H and D{sub 2}.

  10. Introducing the Wittig Reaction.

    ERIC Educational Resources Information Center

    Armstead, D. E. F.

    1979-01-01

    An experiment is described which provides a simple example of the application of the Wittig reaction to the synthesis of unsaturated compounds. The experiment was designed with British HNC chemistry students in mind, but it is also suitable as a project-type exercise for final year GCE A-level students. (Author/BB)

  11. Enantioselective Vinylogous Organocascade Reactions.

    PubMed

    Hepburn, Hamish B; Dell'Amico, Luca; Melchiorre, Paolo

    2016-08-01

    Cascade reactions are powerful tools for rapidly assembling complex molecular architectures from readily available starting materials in a single synthetic operation. Their marriage with asymmetric organocatalysis has led to the development of novel techniques, which are now recognized as reliable strategies for the one-pot enantioselective synthesis of stereochemically dense molecules. In recent years, even more complex synthetic challenges have been addressed by applying the principle of vinylogy to the realm of organocascade catalysis. The key to the success of vinylogous organocascade reactions is the unique ability of the chiral organocatalyst to transfer reactivity to a distal position without losing control on the stereo-determining events. This approach has greatly expanded the synthetic horizons of the field by providing the possibility of forging multiple stereocenters in remote positions from the catalyst's point of action with high selectivity, while simultaneously constructing multiple new bonds. This article critically describes the developments achieved in the field of enantioselective vinylogous organocascade reactions, charting the ideas, the conceptual advances, and the milestone reactions that have been essential for reaching highly practical levels of synthetic efficiency.

  12. Chain Reaction Polymerization.

    ERIC Educational Resources Information Center

    McGrath, James E.

    1981-01-01

    The salient features and importance of chain-reaction polymerization are discussed, including such topics as the thermodynamics of polymerization, free-radical polymerization kinetics, radical polymerization processes, copolymers, and free-radical chain, anionic, cationic, coordination, and ring-opening polymerizations. (JN)

  13. Chemical Reactions at Surfaces

    SciTech Connect

    Michael Henderson and Nancy Ryan Gray

    2010-04-14

    Chemical reactions at surfaces underlie some of the most important processes of today, including catalysis, energy conversion, microelectronics, human health and the environment. Understanding surface chemical reactions at a fundamental level is at the core of the field of surface science. The Gordon Research Conference on Chemical Reactions at Surfaces is one of the premiere meetings in the field. The program this year will cover a broad range of topics, including heterogeneous catalysis and surface chemistry, surfaces in environmental chemistry and energy conversion, reactions at the liquid-solid and liquid-gas interface, electronic materials growth and surface modification, biological interfaces, and electrons and photons at surfaces. An exciting program is planned, with contributions from outstanding speakers and discussion leaders from the international scientific community. The conference provides a dynamic environment with ample time for discussion and interaction. Attendees are encouraged to present posters; the poster sessions are historically well attended and stimulate additional discussions. The conference provides an excellent opportunity for junior researchers (e.g. graduate students or postdocs) to present their work and interact with established leaders in the field.

  14. Reaction Formulation: A Bibliography.

    ERIC Educational Resources Information Center

    Pedrini, D. T.; Pedrini, Bonnie C.

    Reaction formation was studied by Sigmund Freud. This defense mechanism may be related to repression, substitution, reversal, and compensation (or over-compensation). Alfred Adler considered compensation a basic process in his individual psychology. Anna Freud discussed some defense mechanisms, and Bibring, Dwyer, Huntington, and Valenstein…

  15. Lithium Cell Reactions.

    DTIC Science & Technology

    1985-02-01

    Page 1. INVESTIGATION OF CHEMICAL, ELECTROCHEMICAL AND PARASITIC REACTIONS IN LITHIUM - THIONYL CHLORIDE CELLS ....... ................. 1 1.1 INTRODUCTION...OF LITHIUM - THIONYL CHLORIDE CELLS. ................ 56 1.4.1 Carbon Limited Overdischarge...............56 1.4.1.1 Background... LITHIUM THIONYL - CHLORIDE CELLS. .. ............ ...... 101 1.5.1 Background. ....... ............ .... 101 1.5.2 Microphotography

  16. Confronting Combat Stress Reactions

    DTIC Science & Technology

    2010-03-22

    of the scalp, skull , or brain. 4 Combat stress reaction is categorized as a range of behaviors resulting from the stress of battle which decreases...3) experiencing rage aimed at discriminate and indiscriminate targets, (4) psychic numbing or emotional shutdown, (5) alienation from themselves and

  17. A Superintendent's Reaction

    ERIC Educational Resources Information Center

    Lytle, James H.

    2004-01-01

    This article presents a superintendent's reaction to Catherine Marshall and Michael Ward's article on research on social justice and training for leadership. The author states that there is a problem with Marshall and Ward's article which begins with the title, particularly with the word "training." The author contends that there is a significant…

  18. Polymerase chain reaction system

    DOEpatents

    Benett, William J.; Richards, James B.; Stratton, Paul L.; Hadley, Dean R.; Milanovich, Fred P.; Belgrader, Phil; Meyer, Peter L.

    2004-03-02

    A portable polymerase chain reaction DNA amplification and detection system includes one or more chamber modules. Each module supports a duplex assay of a biological sample. Each module has two parallel interrogation ports with a linear optical system. The system is capable of being handheld.

  19. Exocharmic Reactions up Close

    ERIC Educational Resources Information Center

    Ramette, R. W.

    2007-01-01

    The exocharmic reactions that can be observed microscopically are discussed. The students can discover the optimal concentration of an acidic lead nitrate solution, so that a crystal of potassium iodide, nudged to the edge of a drop, results in glinting golden hexagons of lead iodide.

  20. Three Reaction Papers.

    ERIC Educational Resources Information Center

    Coop, Richard H.; And Others

    1982-01-01

    In reaction papers, Richard H. Coop, an educational psychologist, discusses six themes evident in papers on gifted education; B. J. Cox argues that systems theory is a valuable addition to education of identified and potentially gifted students; and Gary D. Fenstermacher argues for specification of educational entitlements of any learner before…

  1. The aromatic ene reaction

    PubMed Central

    Niu, Dawen; Hoye, Thomas R.

    2014-01-01

    The ene reaction is a pericyclic process in which an alkene having an allylic hydrogen atom (the ene donor) reacts with a second unsaturated species (the enophile) to form a new product with a transposed π-bond. The aromatic ene reaction, in which the alkene component is embedded in an aromatic ring, has only been reported in a few (four) instances and has proceeded in low yield (≤6%). Here we show efficient aromatic ene reactions in which a thermally generated aryne engages a pendant m-alkylarene substituent to produce a dearomatized isotoluene, itself another versatile but rare reactive intermediate. Our experiments were guided by computational studies that revealed structural features conducive to the aromatic ene process. We proceeded to identify a cascade comprising three reactions: (i) hexadehydro-Diels-Alder (for aryne generation), (ii) intramolecular aromatic ene, and (iii) bimolecular Alder ene. The power of this cascade is evident from the structural complexity of the final products, the considerable scope, and the overall efficiency of these multi-stage, reagent- and byproduct-free, single-pot transformations. PMID:24345944

  2. UV spectroscopy of Titan's atmosphere, planetary organic chemistry and prebiological synthesis. II - Interpretation of new IUE observations in the 220-335 nm range

    NASA Technical Reports Server (NTRS)

    Courtin, Regis; Wagener, Richard; Mckay, Christopher P.; Caldwell, John; Fricke, Karl-Heinrich

    1991-01-01

    The theoretical model developed by McKay et al. (1989) to characterize the size distribution, thermal structure, and chemical composition of the stratospheric haze of Titan is applied to new 220-335-nm albedo measurements obtained with the long-wavelength prime camera of the IUE during August 1987. Data and model predictions are presented in extensive graphs and discussed in detail. It is shown that a simple model with particles of one size at a given altitude does not accurately reproduce the observed features in all spectral regions, but that good general agreement is obtained using a model with a uniformly mixed layer at 150-600 km and a bimodal distribution of small 'polymer' haze particles (radius less than 20 nm) and larger haze particles (radius 100-500 nm). The number densities implied by this model require, however, a mechanism such as electrostatic charging or reaction kinetics to inhibit coagulation of the smaller particles.

  3. High power room temperature 1014.8 nm Yb fiber amplifier and frequency quadrupling to 253.7 nm for laser cooling of mercury atoms.

    PubMed

    Hu, Jinmeng; Zhang, Lei; Liu, Hongli; Liu, Kangkang; Xu, Zhen; Feng, Yan

    2013-12-16

    An 8 W continuous wave linearly-polarized single-frequency 1014.8 nm fiber amplifier working at room temperature is developed with commercial double-clad single-mode Yb-doped silica fiber. Re-absorption at the laser wavelength and amplified spontaneous emission at longer wavelength are managed by optimizing the amplifier design. The laser has a linewidth of ~24 kHz without noticeable broadening after amplification. Using two resonant cavity frequency doublers, 1.03 W laser at 507.4 nm and 75 mW laser at 253.7 nm are generated with 4 W 1014.8 nm laser. Both absorption and saturated absorption spectra of the (1)S(0) - (3)P(1) transition of atomic mercury are measured with the 253.7 nm laser.

  4. Enhancement of 800 nm upconversion emission in a thulium doped tellurite microstructured fiber pumped by a 1560 nm femtosecond fiber laser

    NASA Astrophysics Data System (ADS)

    Jia, Zhixu; Yao, Chuanfei; Wang, Shunbin; Zheng, Kezhi; Xiong, Liangming; Luo, Jie; Lv, Dajuan; Qin, Guanshi; Ohishi, Yasutake; Qin, Weiping

    2016-04-01

    We report enhanced upconversion (UC) fluorescence in Tm3+ doped tellurite microstructured fibers (TDTMFs) fabricated by using a rod-in-tube method. Under the pumping of a 1560 nm femtosecond fiber laser, ultrabroadband supercontinuum light expanding from ˜1050 to ˜2700 nm was generated in a 4 cm long TDTMF. Simultaneously, intense 800 nm UC emission from the 3H4 → 3H6 transition of Tm3+ was observed in the same TDTMF. Compared to that pumped by a 1560 nm continuous wave fiber laser, the UC emission intensity was enhanced by ˜4.1 times. The enhancement was due to the spectral broadening in the TDTMF under the pumping of the 1560 nm femtosecond fiber laser.

  5. 78 FR 41420 - Notice of Competitive Coal Lease Sale NMNM-126813, NM

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-10

    ... in the BLM Conference Room, New Mexico State Office, 301 Dinosaur Trail, Santa Fe, NM 87508. Sealed bids must be submitted to: Cashier, New Mexico State Office, 301 Dinosaur Trail, Santa Fe, NM 87508... at 301 Dinosaur Trail, Santa Fe, NM 87508 or the Farmington District Office at 6251 College Blvd....

  6. A Feasibility Study of 50 nm Resolution with Low Energy Electron Beam Proximity Projection Lithography

    NASA Astrophysics Data System (ADS)

    Yoshizawa, Masaki; Savas, T. A.

    2002-01-01

    Patterns of 50 nm lines and spaces were demonstrated by low energy electron beam proximity lithography using 47-nm-thick poly methyl methacrylate (PMMA) and stencil masks fabricated by achromatic interference lithography (AIL). The result indicates the validity of the resolution analysis previously reported and the resolution capabilities of low energy electron beam proximity projection lithography (LEEPL) as a 50 nm node technology.

  7. Investigation of the bandwidth of multimode optical fibers used with 1550-nm LED and laser sources

    NASA Technical Reports Server (NTRS)

    White, Preston A., III

    1992-01-01

    Multimode optical fibers are not intended to be used with 1550-nm sources; however, it is desirable to utilize 1300/1550-nm wavelength division multiplexing (WDM) on some multimode fibers at Kennedy Space Center (KSC). No information from fiber vendors nor from the literature is available to support this use. Preliminary studies at KSC have suggested that these fibers might be usable at 1550-nm if the fibers possessed enough bandwidth when sourced by LEDs. Detailed bandwidth studies were made on 12 multimode fibers using 1300- and 1550-nm lasers and LEDs. The results showed that the modal bandwidth at 1550-nm was about 50 percent of the 1300-nm value and that the chromatic dispersion could be predicted by extrapolating the vendor's specifications for wavelengths outside the 1550-nm region. Utilizing these data, predictions of the fiber's optical bandwidth were accurately made. Problems with launch conditions and possible differential attenuation at connectors was noted at 1300-nm but was less significant at 1550-nm. It appears that the multimode fibers studied will offer adequate performance in the 1550-nm region for a number of current KSC needs. Studies of additional fibers are encouraged to gain more confidence and better understanding of the 1550-nm bandwidth of KSC's multimode optical fibers before committing to 1300/1550-nm WDM.

  8. Fractional Erbium laser in the treatment of photoaging: randomized comparative, clinical and histopathological study of ablative (2940nm) vs. non-ablative (1540nm) methods after 3 months*

    PubMed Central

    Borges, Juliano; Cuzzi, Tullia; Mandarim-de-Lacerda, Carlos Alberto; Manela-Azulay, Mônica

    2014-01-01

    BACKGROUND Fractional non-ablative lasers keep the epidermis intact, while fractional ablative lasers remove it, making them theoretically more effective. OBJECTIVES To evaluate the clinical and histological alterations induced by fractional photothermolysis for treating photoaging, comparing the possible equivalence of multiple sessions of 1540nm Erbium, to one session of 2940nm Erbium. METHODS Eighteen patients (mean age 55.9) completed the treatment with three sessions of 1540nm fractional Erbium laser on one side of the face (50 mJ/mB, 15ms, 2 passes), and one session of 2940nm on the other side (5mJ/mB, 0.25ms, 2 passes). Biopsies were performed before and 3 months after treatment. Clinical, histological and morphometric evaluations were carried out. RESULTS All patients presented clinical improvement with no statistically significant difference (p> 0.05) between the treated sides. Histopathology revealed a new organization of collagen and elastic fibers, accompanied by edema, which was more evident with the 2940nm laser. This finding was confirmed by morphometry, which showed a decrease in collagen density for both treatments, with a statistical significance for the 2940nm laser (p > 0.001). CONCLUSIONS Three 1540nm sessions were clinically equivalent to one 2940nm session. The edema probably contributed to the positive results after three months, togheter with the new collagen and elastic fibers organization. The greater edema after the 2940nm session indicates that dermal remodeling takes longer than with 1540nm. It is possible that this histological superiority relates to a more prolonged effect, but a cohort longer than three months is needed to confirm that supposition. PMID:24770501

  9. Aqueous glucose measurement using differential absorption-based frequency domain optical coherence tomography at wavelengths of 1310 nm and 1625 nm

    NASA Astrophysics Data System (ADS)

    John, Pauline; Manoj, Murali; Sujatha, N.; Vasa, Nilesh J.; Rao, Suresh R.

    2015-07-01

    This work presents a combination of differential absorption technique and frequency domain optical coherence tomography for detection of glucose, which is an important analyte in medical diagnosis of diabetes. Differential absorption technique is used to detect glucose selectively in the presence of interfering species especially water and frequency domain optical coherence tomography (FDOCT) helps to obtain faster acquisition of depth information. Two broadband super-luminescent diode (SLED) sources with centre wavelengths 1586 nm (wavelength range of 1540 to 1640 nm) and 1312 nm (wavelength range of 1240 to 1380 nm) and a spectral width of ≍ 60 nm (FWHM) are used. Preliminary studies on absorption spectroscopy using various concentrations of aqueous glucose solution gave promising results to distinguish the absorption characteristics of glucose at two wavelengths 1310 nm (outside the absorption band of glucose) and 1625 nm (within the absorption band of glucose). In order to mimic the optical properties of biological skin tissue, 2% and 10% of 20% intralipid with various concentrations of glucose (0 to 4000 mg/dL) was prepared and used as sample. Using OCT technique, interference spectra were obtained using an optical spectrum analyzer with a resolution of 0.5 nm. Further processing of the interference spectra provided information on reflections from the surfaces of the cuvette containing the aqueous glucose sample. Due to the absorption of glucose in the wavelength range of 1540 nm to 1640 nm, a trend of reduction in the intensity of the back reflected light was observed with increase in the concentration of glucose.

  10. Subcomponent self-assembly of a 4 nm M4 L6 tetrahedron with Zn(II) vertices and perylene bisimide dye edges.

    PubMed

    Frischmann, Peter D; Kunz, Valentin; Stepanenko, Vladimir; Würthner, Frank

    2015-02-09

    Formation of a tetrahedron with >4 nm perylene bisimide (PBI) dye edges and Zn(II) vertices in a one-pot 22 component self-assembly reaction is reported. The luminescent polyhedron equilibrates to a Zn2 L3 helicate and disassembles upon dilution. Insights into the subcomponent self-assembly of extended PBI ligands help to refine design rules for constructing large photofunctional metallosupramolecular hosts.

  11. Mask design rules (45 nm): time for standardization

    NASA Astrophysics Data System (ADS)

    Mason, Mark; Progler, Christopher J.; Martin, Patrick; Ham, Young-Mog; Dillon, Brian; Pack, Robert; Heins, Mitch; Gookassian, John; Garcia, John; Boksha, Victor

    2005-11-01

    Time-to-mask (ttm) has been growing exponentially in the subwavelength era with the increased application of advanced RET's (Resolution Enhancement Technology). Not only are a greater number of design/mask layers impacted but more-and-more layers also have more severe restrictions on critical dimension uniformity (CDU) despite operating at a very low k1 factors necessitating rigorous but practical tolerancing. Furthermore, designs are also more complex, may be built up from blocks spanning different design styles, and occupy increasingly-large Rayleigh field areas. Given these factors and scales, it's no wonder that the cycle time for verification of a design following RET, is growing however it is doing so exponentially and that this is a critical factor impeding ttm. Until an unambiguously interprable and standard Mask Design Rule (MaskDR) set is created, neither the designer nor the mask supplier can reliably verify manufacturability of the mask for the simple reason that ambiguity and inter-rule conflict are at the source of the problem and that the problem increasingly requires cooperation spanning a large ecosystem of tool, IP, and mask suppliers all needing to essentially speak the same language. Since the 130 nm node, Texas Instruments has enforced a strict set of mask rule checks (MRCs) in their mask data preparation (MDP) flow based on MaskDRs negotiated with their mask suppliers. The purpose of this effort has been to provide an a-priori guarantee that the data shipped to the mask shop can be used to manufacture a mask reliably and with high yield both from a mask standpoint and from the silicon standpoint. As has been reported earlier, mask manufacturing rules are usually determined from assumed or experimentally acquired/validated mask-manufacturing limits. These rules are then applied during RET/MDP data treatment to guide and/or limit pattern correction strategies. With increasing RET and low-k1 lithography challenges, the importance of MRCs

  12. Inorganic Reaction Mechanisms. Part I

    ERIC Educational Resources Information Center

    Cooke, D. O.

    1976-01-01

    Provides a collection of data on the mechanistic aspects of inorganic chemical reactions. Wherever possible includes procedures for classroom demonstration or student project work. The material covered includes gas phase reactions, reactions in solution, mechanisms of electron transfer, the reaction between iron III and iodine, and hydrolysis. (GS)

  13. What Is a Reaction Rate?

    ERIC Educational Resources Information Center

    Schmitz, Guy

    2005-01-01

    The definition of reaction rate is derived and demonstrations are made for the care to be taken while using the term. Reaction rate can be in terms of a reaction property, the extent of reaction and thus it is possible to give a definition applicable in open and closed systems.

  14. Preliminary characterisation of new glass reference materials (GSA-1G, GSC-1G, GSD-1G and GSE-1G) by laser ablation-inductively coupled plasma-mass spectrometry using 193 nm, 213 nm and 266 nm wavelengths

    USGS Publications Warehouse

    Guillong, M.; Hametner, K.; Reusser, E.; Wilson, S.A.; Gunther, D.

    2005-01-01

    New glass reference materials GSA-1G, GSC-1G, GSD-1G and GSE-1G have been characterised using a prototype solid state laser ablation system capable of producing wavelengths of 193 nm, 213 nm and 266 nm. This system allowed comparison of the effects of different laser wavelengths under nearly identical ablation and ICP operating conditions. The wavelengths 213 nm and 266 nm were also used at higher energy densities to evaluate the influence of energy density on quantitative analysis. In addition, the glass reference materials were analysed using commercially available 266 nm Nd:YAG and 193 nm ArF excimer lasers. Laser ablation analysis was carried out using both single spot and scanning mode ablation. Using laser ablation ICP-MS, concentrations of fifty-eight elements were determined with external calibration to the NIST SRM 610 glass reference material. Instead of applying the more common internal standardisation procedure, the total concentration of all element oxide concentrations was normalised to 100%. Major element concentrations were compared with those determined by electron microprobe. In addition to NIST SRM 610 for external calibration, USGS BCR-2G was used as a more closely matrix-matched reference material in order to compare the effect of matrix-matched and non matrix-matched calibration on quantitative analysis. The results show that the various laser wavelengths and energy densities applied produced similar results, with the exception of scanning mode ablation at 266 nm without matrix-matched calibration where deviations up to 60% from the average were found. However, results acquired using a scanning mode with a matrix-matched calibration agreed with results obtained by spot analysis. The increased abundance of large particles produced when using a scanning ablation mode with NIST SRM 610, is responsible for elemental fractionation effects caused by incomplete vaporisation of large particles in the ICP.

  15. The dynamics of femtosecond pulsed laser removal of 20 nm Ni films from an interface

    NASA Astrophysics Data System (ADS)

    Schrider, Keegan J.; Torralva, Ben; Yalisove, Steven M.

    2015-09-01

    The dynamics of femtosecond laser removal of 20 nm Ni films on glass substrates was studied using time-resolved pump-probe microscopy. 20 nm thin films exhibit removal at two distinct threshold fluences, removal of the top 7 nm of Ni above 0.14 J/cm2, and removal of the entire 20 nm film above 0.36 J/cm2. Previous work shows the top 7 nm is removed through liquid spallation, after irradiation the Ni melts and rapidly expands leading to tensile stress and cavitation within the Ni film. This work shows that above 0.36 J/cm2 the 20 nm film is removed in two distinct layers, 7 nm and 13 nm thick. The top 7 nm layer reaches a speed 500% faster than the bottom 13 nm layer at the same absorbed fluence, 500-2000 m/s and 300-700 m/s in the fluence ranges studied. Significantly different velocities for the top 7 nm layer and bottom 13 nm layer indicate removal from an interface occurs by a different physical mechanism. The method of measuring film displacement from the development of Newton's rings was refined so it could be shown that the 13 nm layer separates from the substrate within 70 ps and accelerates to its final velocity within several hundred picoseconds. We propose that removal of the bottom 13 nm is consistent with heterogeneous nucleation and growth of vapor at the Ni-glass interface, but that the rapid separation and acceleration of the 13 nm layer from the Ni-glass interface requires consideration of exotic phases of Ni after excitation.

  16. Laser-induced reactions in energetic materials

    NASA Astrophysics Data System (ADS)

    Ling, Ping

    1999-07-01

    Several energetic materials have been investigated under shock wave loading, heating, and photodissociation. This dissertation highlights some efforts to understand energetic material from an angle of basic physical processes and elementary chemical reactions. The first series of experiments was performed to study laser-generated shock waves in energetic materials. Shock waves are generated by pulsed laser vaporization of thin aluminum films. The rapidly expanding aluminum plasma launches a shock wave into the adjacent layer of energetic material, initiating chemical reactions. The shock velocity has been measured by a velocity interferometer. Shock pressures as high as 8 GPa have been generated in this manner. A simple model is proposed to predict laser-generated shock pressure. Several energetic materials have been studied under laser- generated shock wave. The second series of experiments was conducted to study thermal decomposition and photodissociation of energetic materials. Glycidyl azide polymer (GAP) and poly(glycidyl nitrate) (PGN) have been investigated by pulsed infrared laser pyrolysis and ultraviolet laser photolysis of thin films at 17-77 K. Reactions are monitored by transmission infrared spectroscopy. Photolysis of GAP at 266 nm shows that the initial reaction steps are elimination of molecular nitrogen with subsequent formation of imines. Thermal decomposition of GAP by infrared laser pyrolysis reveals products similar to the UV experiments after warming. Laser pyrolysis of PGN indicated that the main steps of decomposition are elimination of NO2 and CH2O from the nitrate ester functional group. It seems that the initial thermal decomposition mechanism of GAP and PGN are the same from heating rate of several degrees per second to 107 oC/s. The third series of experiments is about detailed study of photodissociation mechanism of methyl nitrate. Photodissociation of methyl nitrate isolated in an argon matrix at 17 K has been investigated by 266 nm

  17. Laser Application in Dentistry: Irradiation Effects of Nd:YAG 1064 nm and Diode 810 nm and 980 nm in Infected Root Canals—A Literature Overview

    PubMed Central

    Kuypers, Thorsten; Gutknecht, Norbert

    2016-01-01

    Objective. In endodontics, Nd:YAG laser (1064 nm) and diode laser (810 nm and 980 nm) devices are used to remove bacteria in infected teeth. A literature review was elaborated to compare and evaluate the advantages and disadvantages of using these lasers. Methods. Using combined search terms, eligible articles were retrieved from PubMed and printed journals. The initial search yielded 40 titles and 27 articles were assigned to full-text analysis. The studies were classified based upon laser source, laser energy level, duration/similarity of application, and initial and final bacterial count at a minimum of 20 prepared root canals. Part of the analysis was only reduced microorganisms and mechanically treated root canals upon preparation size of ISO 30. All studies were compared to evaluate the most favorable laser device for best results in endodontic therapy. Results. A total of 22 eligible studies were found regarding Nd:YAG laser 1064 nm. Four studies fulfilled all demanded criteria. Seven studies referring to the diode laser 980 nm were examined, although only one fulfilled all criteria. Eleven studies were found regarding the diode laser 810 nm, although only one study fulfilled all necessary criteria. Conclusions. Laser therapy is effective in endodontics, although a comparison of efficiency between the laser devices is not possible at present due to different study designs, materials, and equipment. PMID:27462611

  18. Visible to near IR luminescence spectrum of Radachlorin under excitation at 405 nm

    NASA Astrophysics Data System (ADS)

    Belik, V. P.; Gadzhiev, I. M.; Petrenko, M. V.; Petrov, M. A.; Semenova, I. V.; Vasyutinskii, O. S.

    2016-11-01

    The luminescence spectrum of Radachlorin dissolved in water in the 600-1350 nm spectral range excited by 405 nm light has been recorded at the first time. The spectrum contains a wide band with peaks centered at 662, 715, 940, and 1274 nm. Relative contributions to the spectrum from different sources have been evaluated. Ratio of the singlet oxygen signal to the total signal intensity averaged over the 1240-1300 nm spectral range was determined to be 40%. Isolation of the singlet oxygen signal from the total signal at 1274 nm has been achieved by means of a spectral-resolved TCSPC detection technique.

  19. High-efficiency fiber laser at 1018 nm using Yb-doped phosphosilicate fiber.

    PubMed

    Wang, Jianhua; Chen, Gui; Zhang, Lei; Hu, Jinmeng; Li, Jinyan; He, Bing; Chen, Jinbao; Gu, Xijia; Zhou, Jun; Feng, Yan

    2012-10-10

    A high-efficiency fiber laser at 1018 nm using homemade Yb-doped phosphosilicate fiber is demonstrated. The fiber shows blueshifted emission spectrum compared to Yb-doped aluminosilicate fiber, and is considered favorable for the short wavelength Yb-doped fiber laser. With a 7 m gain fiber, up to 22.8 W output at 1018 nm is achieved with an optical efficiency of 53%. The amplified spontaneous emission at 1030 nm is suppressed to 50 dB below the 1018 nm laser. This work shows that highly-efficient fiber laser at 1018 nm can be obtained with Yb-doped phosphosilicate fiber.

  20. Nd:YAG laser diode-pumped directly into the emitting level at 938 nm.

    PubMed

    Sangla, Damien; Balembois, François; Georges, Patrick

    2009-06-08

    We present the first demonstration of Nd:YAG laser pumped directly in band at 938 nm with a high-brightness fiber-coupled laser diode. Up to 6 W of CW laser emission at 1064 nm have been obtained under an absorbed pump power of 28 W at 938 nm. A comparison between 808 nm and 938 nm pumping, realized by thermal cartography, demonstrates the very low heat generation of in-band pumping. Numerical simulations were also implemented to study and discuss the laser performance of our system.