다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Organic solar cell research has developed during the past 30 years, but especially in the last decade it has attracted scientific and economic interest triggered by a rapid increase in power conversion efficiencies. This was achieved by the introduction of new materials, improved materials engineering, and more sophisticated device structures. Today, solar power conversion efficiencies in excess of 3% have been accomplished with several device concepts. Though efficiencies of these thin-film organicdevices have not yet reached those of their inorganic counterparts (η ≈ 10–20%); the perspective of cheap production (employing, e.g., roll-to-roll processes) drives the development of organic photovoltaic devices further in a dynamic way. The two competitive production techniques used today are either wet solution processing or dry thermal evaporation of the organic constituents. The field of organic solar cells profited well from the development of light-emitting diodes based on similar technologies, which have entered the market recently. We review here the current status of the field of organic solar cells and discuss different production technologies as well as study the important parameters to improve their performance.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0884291400094498

Organic solar cells: An overview

12.2.2. Four-Wave Mixing (FWM) 4849 12.2.3. Dye Aggregation 4850 12.2.4. Optoelectronic Nanodevices 4850 12.3. Sensor 4851 12.3.1. Chemical Sensor 4851 12.3.2. Biological Sensor 4851 12.4. Catalysis 4852 13. Conclusion and Perspectives 4852 14. Abbreviations 4853 15. Acknowledgements 4854 16. References 4854 * Corresponding author E-mail: tpal@chem.iitkgp.ernet.in. † Raidighi College. § Indian Institute of Technology. 4797 Chem. Rev. 2007, 107, 4797−4862

Interparticle Coupling Effect on the Surface Plasmon Resonance of Gold Nanoparticles: From Theory to Applications

Two-photon absorption has important advantages over conventional one-photon absorption, which has led to applications in microscopy, microfabrication, three-dimensional data storage, optical power limiting, up-converted lasing, photodynamic therapy, and for the localized release of bio-active species. These applications have generated a demand for new dyes with high two-photon absorption cross-sections. This Review introduces the theory of two-photon absorption, surveys the wide range of potential applications, and highlights emerging structure-property correlations that can serve as guidelines for the development of efficient two-photon dyes.

Two-photon absorption and the design of two-photon dyes.

This thesis explores transport phenomena in nanochannels on a chip. Fundamental nanofluidic ionic studies form the basis for novel separation and preconcentration applications for proteomic purposes. The measurements were performed with 50-nm-high 1D nanochannels, which are easily accessible from both sides by two microchannels. Nanometer characteristic apertures were manufactured in the bonded structure of Pyrex-amorphous silicon – Pyrex, in which the thickness of the amorphous silicon layer serves as a spacer to define the height of the nanochannels. The geometry of the nanometer-sized apertures is well defined, which simplifies the modeling of the transport across them. Compared to biological pores, the present nanochannels in Pyrex offer increased stability. Fundamental characteristics of nanometer-sized apertures were obtained by impedance spectroscopy measurements of the nanochannel at different ionic strengths and pH values. A conductance plateau (on a log-log scale) was modeled and measured, establishing due to the dominance of the surface charge density in the nanochannels, which induces an excess of mobile counterions to maintain electroneutrality. The nanochannel conductance can be regulated at low ionic strengths by pH adjustment, and by an external voltage applied on the chip to change the zeta potential. This field-effect allows the regulation of ionic flow which can be exploited for the fabrication of nanofluidic devices. Fluorescence measurements confirm that 50-nm-high nanochannels show an exclusion of co-ions and an enrichment of counterions at low ionic strengths. This permselectivity is related to the increasing thickness of the electrical double layer (EDL) with decreasing salt concentrations, which results in an EDL overlap in an aperture if the height of the nanochannel and the thickness of the EDL are comparable in size. The diffusive transport of charged species and therefore the exclusion-enrichment effect was described with a simple model based on the Poisson-Boltzmann equation. The negatively charged Pyrex surface of the nanometer characteristic apertures can be inversed with chemical surface pretreatments, resulting in an exclusion of cations and an enrichment of anions. When a pressure gradient is applied across the nanochannels, charged molecules are electrostatically rejected at the entrance of the nanometer-sized apertures, which can be used for separation processes. Proteomic applications are presented such as the separation and preconcentration of proteins. The diffusion of Lectin proteins with different isoelectric points and very similar compositions were controlled by regulating the pH value of the buffer. When the proteins are neutral at their pI value, the diffusion coefficient is maximal because the biomolecules does not interact electrostatically with the charged surfaces of the nanochannel. This led to a fast separation of three Lectin proteins across the nanochannel. The pI values measured in this experiment are slightly shifted compared to the values obtained with isoelectric focusing because of reversible adsorption of proteins on the walls which affects the pH value in the nanochannel. An important application in the proteomic field is the preconcentration of biomolecules. By applying an electric field across the nanochannel, anionic and cationic analytes were preconcentrated on the cathodic side of the nanometer-sized aperture whereas on the anodic side depletion of ions was observed. This is due to concentration polarization, a complex of effects related to the formation of ionic concentration gradients in the electrolyte solution adjacent to an ion-selective interface. It was measured that the preconcentration factor increased with the net charge of the molecule, leading to a preconcentration factor of > 600 for rGFP proteins in 9 minutes. Such preconcentrations are important in micro total analysis systems to achieve increased detection signals of analytes contained in dilute solutions. Compared to cylindrical pores, our fabrication process allows the realization of nanochannels on a chip in which the exclusion-enrichment effect and a big flux across the nanometer-sized aperture can be achieved, showing the interest for possible micro total analysis system applications. The described exclusion-enrichment effect as well as concentration polarization play an important role in transport phenomena in nanofluidics. The appendix includes preliminary investigations in DNA molecule separation and fluorescence correlation spectroscopy measurements, which allows investigating the behavior of molecules in the nanochannel itself.

/pdf/transport-phenomena-in-nanofluidics-1di3nwdyom.pdf

Transport phenomena in nanofluidics

Preface Introduction I: Nanoscale Fabrication and Characterization 1 Nanolithography LR Harriott, R Hull 2 Self-Assembly And Self-Organization R Shenhar, TB Norsten, VM Rotello 3 Scanning Probe Microscopes K-W Ng II: Nanomaterials and Nanostructures 4 The Geometry of Nanoscale Carbon V Crespi 5 Fullerenes H Dorn, JC Duchamp 6 Carbon Nanotubes BW Smith, DE Luzzi 7 Quantum Dots AB Denison, LJ Hope-Weeks, RW Meulenberg, LJ Terminello 8 Nanocomposites RC Cammarata III: Nanoscale and Molecular Electronics 9 Advances In Microelectronics - From Microscale To Nanoscale Devices J Van Der Spiegel 10 Molecular Electronics M Zwolak, M Di Ventra 11 Single Electron Transistors JG Lu IV: Nanotechnology in Magnetic Systems 12 Semiconductor Nanostructures For Quantum Computation ME Flatte 13 Magnetoresistive Materials And Devices O Heinonen 14 Nanotechnology In Magnetic Storage JA Katine, RE Fontana Jr V: Nanotechnology in Integrative Systems 15 Introduction To Integrative Systems M Gaitan 16 Nanoelectromechanical Systems S Evoy, M Duemling, T Jaruhar 17 Micromechanical Sensors P Datskos, NV Lavrik VI: Nanoscale Optoelectronics 18 Quantum-Confined Optoelectronic Systems S Fafard 19 Organic Optoelectronic Nanostructures JR Heflin20 Photonic Crystals Y Xia, K Kamata, Y Lu VII: Nanobiotechnology 21 Biomemetic Nanostructures DE Dische 22 Biomolecular Motors J Schmidt, C Montemagno 23 Nanofluidics J Han

Introduction to Nanoscale Science and Technology

Nonlinear optical properties of linear chains and electron-correlation effects.

NONLINEAR optical phenomena form the basis for all-optical devices such as optically bistable switches and nonlinear directional couplers1. The suitability of a material for these device applications requires a large magnitude of the relevant nonlinear effect (in this case, the third-order optical susceptibility & psi;(3), which is related to the intensity-dependent refractive index) and a small signal attenu-ation arising from the linear optical absorption. Conjugated organic molecules and polymers are of particular interest in this context: the delocalized π-electron systems of these materials give rise to relatively large values of & psi;(3) with extremely fast response times, in wavelength regimes where there is minimal background absorption. Previous theoretical studies2 suggested a new enhance-ment mechanism for the nonlinear optical processes in these materials through population of the electronic excited states. Here we show that by optically exciting a linear conjugated molecule at one wavelength into an electronic excited state for a sufficient length of time to perform the nonlinear optical measurement, the value of & psi;(3) can be enhanced by more than two orders of magnitude without increasing optical absorption at the probe wavelength.

Excited-state enhancement of optical nonlinearities in linear conjugated molecules

An ionically self-assembled monolayer (ISAM) technique for thin-film deposition has been employed to fabricate materials possessing the noncentrosymmetry that is requisite for a second-order, χ(2), nonlinear optical response. As a result of the ionic attraction between successive layers, the ISAM χ(2) films self-assemble into a noncentrosymmetric structure that has exhibited no measurable decay of χ(2) at room temperature over a period of more than one year. The second-harmonic intensity of the films exhibits the expected quadratic dependence on film thickness up to at least 100 bilayers, corresponding to a film thickness of 120 nm. The polarization dependence of the second-harmonic generation yields a value of 35° for the average tilt angle of the nonlinear optical chromophores away from the surface normal.

/pdf/thickness-dependence-of-second-harmonic-generation-in-thin-howr0yg727.pdf

Thickness dependence of second-harmonic generation in thin films fabricated from ionically self-assembled monolayers

We demonstrate that ionic self-assembled multilayers (ISAMs) adsorbed on long period gratings (LPGs) function effectively as biosensors using biotin–streptavidin as a demonstration bioconjugate pair. Biotin, streptavidin, and anti-streptavidin were deposited onto the ISAM-coated LPG sequentially, each inducing a measurable resonant wavelength shift of the LPG. Control experiments verified the specificity of the biosensor system. Furthermore, we demonstrate that ISAM coated turnaround point LPGs could serve as highly sensitive biosensors that exhibit a change in transmitted intensity rather than resonant wavelength. Experimental measurements confirm that ISAM-coated LPGs provide an attractive platform for building efficient and high-performance optical sensors.

James R. Heflin

Papers

Introduction to Nanoscale Science and Technology

Nonlinear optical properties of linear chains and electron-correlation effects.

Excited-state enhancement of optical nonlinearities in linear conjugated molecules

Thickness dependence of second-harmonic generation in thin films fabricated from ionically self-assembled monolayers

Biosensors employing ionic self-assembled multilayers adsorbed on long-period fiber gratings