A. Water Exchange 2326 B. Proton Exchange 2327 C. Electronic Relaxation 2327 D. Relaxivity 2331 E. Outerand Second-Sphere Relaxivity 2334 F. Methods of Improving Relaxivity 2336 V. Macromolecular Conjugates 2336 A. Introduction 2336 B. General Conjugation Methods 2336 C. Synthetic Linear Polymers 2336 D. Synthetic Dendrimer-Based Agents 2338 E. Naturally Occurring Polymers (Proteins, Polysaccharides, and Nucleic Acids) 2339

https://mriquestions.com/uploads/3/4/5/7/34572113/lauffer_1999_review.pdf

Gadolinium(III) Chelates as MRI Contrast Agents: Structure, Dynamics, and Applications

This paper reviews the history, the present status and possible future developments of photovoltaic (PV) materials for terrestrial applications. After a brief history and introduction of the photovoltaic effect theoretical requirements for the optimal performance of materials for pn-junction solar cells are discussed. Most important are efficiency, long-term stability and, not to be neglected, lowest possible cost. Today the market is dominated by crystalline silicon in its multicrystalline and monocrystalline form. The physical and technical limitations of this material are discussed. Although crystalline silicon is not the optimal material from a solid state physics point of view it dominates the market and will continue to do this for the next 5–10 years. Because of its importance a considerable part of this review deals with materials aspects of crystalline silicon. For reasons of cost only multicrystalline silicon and monocrystalline Czochralski (Cz) crystals are used in practical cells. Light induced instability in this Cz-material has recently been investigated and ways to eliminate this effect have been devised. For future large scale production of crystalline silicon solar cells development of a special solar grade silicon appears necessary. Ribbon growth is a possibility to avoid the costly sawing process. A very vivid R&D area is thin-film crystalline silicon (about 5–30 μm active layer thickness) which would avoid the crystal growing and sawing processes. The problems arising for this material are: assuring adequate light absorption, assuring good crystal quality and purity of the films, and finding a substrate that fulfills all requirements. Three approaches have emerged: high-temperature, low-temperature and transfer technique. Genuine thin-film materials are characterized by a direct band structure which gives them very high light absorption. Therefore, these materials have a thickness of only one micron or less. The oldest such material is amorphous silicon which is the second most important material today. It is mainly used in consumer products but is on the verge to also penetrate the power market. Other strong contenders are chalcogenides like copper indium diselenide (CIS) and cadmium telluride. The interest has expanded from CuInSe 2 , to CuGaSe 2 , CuInS 2 and their multinary alloys Cu(In,Ga)(S,Se) 2 . The two deposition techniques are either separate deposition of the components followed by annealing on one hand or coevaporation. Laboratory efficiencies for small area devices are approaching 19% and large area modules have reached 12%. Pilot production of CIS-modules has started in the US and Germany. Cadmium telluride solar cells also offer great promise. They have only slightly lower efficiency and are also at the start of production. In the future other materials and concepts can be expected to come into play. Some of these are: dye sensitized cells, organic solar cells and various concentrating systems including III/V-tandem cells. Theoretical materials that have not yet been realized are Auger generation material and intermediate metallic band material.

Photovoltaic materials, history, status and outlook

Reference LCIB-ARTICLE-2007-010doi:10.1021/cr030726oView record in Web of Science Record created on 2007-02-14, modified on 2017-05-12

Inorganic and bioinorganic solvent exchange mechanisms.

Organotin(IV)n+ complexes formed with biologically active ligands: equilibrium and structural studies, and some biological aspects

Water exchange on metal ions: experiments and simulations

Extended x‐ray absorption fine structure (EXAFS) measurements were performed for concentrated aqueous rare earth perchlorate solutions (R=28; R is the moles of water per mole of salt) in the liquid state at room temperature and in the glassy state at liquid nitrogen temperature. The quantitative analysis of the EXAFS data has revealed that the hydration number changes from about nine for light rare earth ions to about eight for heavy rare earth ions through the intermediate ions of Sm3+ ∼Eu3+ in both liquid and glassy states. The average Ln3+ –OH2 distances were determined and they are in agreement with previously reported values from x‐ray and neutron diffraction. The Debye–Waller factor of the average Ln3+ –OH2 bonds for the light rare earth ions was larger than that for the heavy ions, suggesting that the hydration shell of the light rare earth ions is statically disordered, consisting of different Ln3+ –OH2 bonds.

An extended x‐ray absorption fine structure study of aqueous rare earth perchlorate solutions in liquid and glassy states

A general formula for the optical-luminescence yield spectra arising from the core excitation is derived, making use of a simple phenomenological model. In this model, it is assumed that various excitations from core electron levels give rise to an identical luminescence in the individual yields. A smaller yield of the inner-core 'electron excitation than that of the outer-core electron excitation results in a variety of anomalous yield spectra such as those with a negative jump, a positive jump with an inverted oscillation part, and an overtone oscillation. Effective thickness is introduced to explain the optical-luminescence yield spectrum of an opaque powdered specimen

Optical-luminescence yield spectra produced by x-ray excitation.

EXAFS study of iron(III) complexes of sugar-type ligands

Concentration dependence of EXAFS and XANES of copper(II) perchlorate aqueous solution: comparison of solute structure in liquid and glassy states

It is revealed from the analysis of Ag K-edge EXAFS that silver(I) is surrounded tetrahedrally by four solvent molecules in liquid ammonia, pyridine, and acetonitrile solutions with Ag–N distances of 2.31, 2.29, and 2.24 A, respectively.

Masaharu Nomura

Papers

An extended x‐ray absorption fine structure study of aqueous rare earth perchlorate solutions in liquid and glassy states

Optical-luminescence yield spectra produced by x-ray excitation.

EXAFS study of iron(III) complexes of sugar-type ligands

Concentration dependence of EXAFS and XANES of copper(II) perchlorate aqueous solution: comparison of solute structure in liquid and glassy states

Silver(I) solvation in some N-donor solvents from Ag K-edge EXAFS