Article on chemical toxicity correlations for several fish species based on the Abraham solvation parameter model.

Article discussing the mathematical representation of the solubility of electrolytes in binary solvent mixtures using the Jouyban-Acree model.

Article discussing the calculation of the viscosity of binary liquids at various temperatures using Jouyban-Acree model.

Article discussing a unified cosolvency model for calculating solute solubility in mixed solvents.

Article on the transcriptome analysis of alfalfa glandular trichomes.

Article on methyl jasmonate and yeast elicitor induce differential transcriptional and metabolic re-programming in cell suspension cultures of the model legume Medicago truncatula.

Article on the mathematical representation of solute solubility in binary mixture of supercritical fluids by the Jouyban-Acree model.

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The composition of the electrolyte is known to greatly influence the performance of dye-sensitized solar cells. It has been speculated that some components of the electrolyte passivate the TiO2 surface against recombination; however, this has never been confirmed experimentally. We hereby present the first case of passivation of the TiO2 surface against recombination by an additive in the electrolyte. Even though the additive also causes a downward movement of the TiO2 bands, suppression of recombination prevails and an overall improvement in open-circuit photovoltage is observed. This work was conducted in collaboration with the DOE Office of Science program.

The purpose of the process integration project of the National Center for Photovoltaics (NCPV) is to develop an infrastructure that will allow researchers to gain new knowledge that is difficult--if not impossible--to obtain with existing equipment. This difficulty is due, in part, to the state of our existing tool set, which lacks sufficient in-situ or real-time measurement capabilities, or lacks access to analytical tools where the sample remains in a controlled environment between deposition and processing or measurement. This new infrastructure will provide flexible and robust integration of deposition, processing (etching, annealing, etc.), and characterization tools via a standardized transfer interface such that samples move between tools in a controlled ambient. This concept will also require the cooperation of experts from various material technologies and characterization disciplines to work directly with each other to obtain answers to key scientific and technological questions. Ultimately, this synergistic effort between NREL staff, universities, and the photovoltaic (PV) industry--around an integrated tool base--will add to the PV knowledge base and help move many PV technologies forward.

The Fourier Transform Infrared Spectroscopy (FTIR) Laboratory supports the Solar Energy Technologies Program through the measurement and characterization of solar energy-related materials and devices. The FTIR technique is a fast, accurate, and reliable method for studying molecular structure and composition. This ability to identify atomic species and their bonding environment is a powerful combination that finds use in many research and development efforts. A brief overview of the technical approach used is contained in Section 2 of this report. Because of its versatility and accessibility, the FTIR Laboratory is a valuable contributor to the Solar Energy Technologies Program. The laboratory provides support for, and collaborates with, several in-house programs as well as our industry and university partners. By the end of FY 2004, the FTIR Laboratory performed over 1100 measurements on PV-related materials. These contributions resulted in conference and workshop presentations and several peer-reviewed publications. A brief summary of a few of these efforts is contained in Section 3 of this report.

Oxygenated nanocrystalline CdS films show improved solar cell performance, but the physics and mechanism underlying this are not yet clearly understood. Raman study provides complementary information to the understanding obtained from other experimental investigations. A comprehensive analysis of the existing experimental data (including x-ray diffraction, transmission, transmission electron microscopy, and Raman) has led to the following conclusions: (1) The O-incorporation forms CdS1-xOx alloy nano-particles. (2) The observed evolution of the electronic structure is the result of the interplay between the alloy and quantum confinement effect. (3) The blue-shift of the LO phonon Raman peak is primarily due to the alloying effect. (4) Some oxygen atoms have taken the interstitial sites.

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Using an ultracapacitor in conjunction with a battery in a hybrid vehicle combines the power performance of the former with the greater energy storage capability of the latter.

To foster continued growth in the U.S. photovoltaic (PV) industry, the U.S. Department of Energy initiated the PV Manufacturing R&D (PVMR&D) Project--a partnership with U.S. PV industry participants to perform cost-shared manufacturing research and development. Throughout FY 2004, PVMR&D managed fourteen subcontracts across the industry. The impact of PVMR&D is quantified by reductions in direct module manufacturing costs, scale-up of existing PV production capacity, and accrual of cost savings to the public and industry. An analysis of public and industry investment shows that both recaptured funds by mid-1998 based on estimated manufacturing cost savings from PVMR&D participation. Since project inception, total PV manufacturing capacity has increased from 14 MW to 201 MW at the close of 2003, while direct manufacturing costs declined from $5.55/W to $2.49/W. These results demonstrate continued progress toward the overriding goals of the PVMR&D project.

We present the results of an ab initio study of elastic scattering and vibrational excitation of NO by electron impact in the low-energy (0-2 eV) region where the cross sections are dominated by resonance contributions. The 3Sigma-, 1Delta and 1Sigma+ NO- resonance lifetimes are taken from our earlier study [Phys. Rev. A 69, 062711 (2004)], but the resonance energies used here are obtained from new configuration-interaction studies. Here we employ a more elaborate nonlocal treatment of the nuclear dynamics, which is found to remedy the principal deficiencies of the local complex potential model we employed in our earlier study, and gives cross sections in better agreement with the most recent experiments. We also present cross sections for dissociative electron attachment to NO leading to groundstate products. The calculations show that, while the peak cross sections starting from NO in its ground vibrational state are very small, the cross sections are extremely sensitive to vibrational excitation of the target and should be readily observable for target NO molecules excited to v = 10 and above.

In FY99, Solar Heating and Lighting set the goal to reduce the life-cycle cost of saved-energy for solar domestic hot water (SDHW) systems in mild climates by 50%, primarily through use of polymer technology. Two industry teams (Davis Energy Group/SunEarth (DEG/SE) and FAFCO) have been developing un-pressurized integral-collector-storage (ICS) systems having load-side heat exchangers, and began field-testing in FY04. DEG/SE?s ICS has a rotomolded tank and thermoformed glazing. Based upon manufacturing issues, costs, and poor performance, the FAFCO team changed direction in late FY04 from an un-pressurized ICS to a direct thermosiphon design based upon use of pool collectors. Support for the teams is being provided for materials testing, modeling, and system testing. New ICS system models have been produced to model the new systems. A new ICS rating procedure for the ICS systems is undergoing testing and validation. Pipe freezing, freeze protection valves, and overheating have been tested and analyzed.

In recent years there has been a revival of interest in Fixed Field Alternating Gradient (FFAG) accelerators. In Japan a number have been built, or are under construction. A new non-scaling approach to the FFAG reduces the required orbit offsets during acceleration and the size of the required aperture, while maintaining the advantage of the low cost magnets associated with fixed fields. An advantage of the non-scaling FFAG accelerator, with respect to synchrotrons, is the fixed field and hence the possibility of high current and high repetition rate for spot scanning. There are possible advantages of the nonscaling design with respect to fixed-field cyclotrons. The non-scaling FFAG allows strong focusing and hence smaller aperture requirements compared to scaling designs, thus leading to very low losses and better control over the beam. We present, here, a non-scaling FFAG designed to be used for proton therapy.

The National Center for Photovoltaics sponsored the 15th Workshop on Crystalline Silicon Solar Cells & Modules: Materials and Processes, held in Vail, CO, August 7-10, 2005. This meeting provided a forum for an informal exchange of technical and scientific information between international researchers in the photovoltaic and relevant non-photovoltaic fields. The workshop addressed the fundamental properties of PV silicon, new solar cell designs, and advanced solar cell processing techniques. A combination of oral presentations by invited speakers, poster sessions, and discussion sessions reviewed recent advances in crystal growth, new cell designs, new processes and process characterization techniques, and cell fabrication approaches suitable for future manufacturing demands. The theme of this year's meeting was 'Providing the Scientific Basis for Industrial Success.' Specific sessions during the workshop included: Advances in crystal growth and material issues; Impurities and defects in Si; Advanced processing; High-efficiency Si solar cells; Thin Si solar cells; and Cell design for efficiency and reliability module operation. The topic for the Rump Session was ''Si Feedstock: The Show Stopper'' and featured a panel discussion by representatives from various PV companies.

Real-time spectroscopic ellipsometry (RTSE) has proven to be an exceptionally valuable tool in the optimization of hot wire CVD (HWCVD) growth of both silicon heterojunction (SHJ) solar cells and thin epitaxial layers of crystal silicon (epi-Si). For SHJ solar cells, RTSE provides real-time thickness information and rapid feedback on the degree of crystallinity of the thin intrinsic layers used to passivate the crystal silicon (c-Si) wafers. For epi-Si growth, RTSE provides real-time feedback on the crystallinity and breakdown of the epitaxial growth process. Transmission electron microscopy (TEM) has been used to verify the RTSE analysis of thickness and crystallinity. In contrast to TEM, RTSE provides feedback in real time or same-day, while TEM normally requires weeks. This rapid feedback has been a key factor in the rapid progress of both the SHJ and epi-Si projects.

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The GaAsN alloy can have a band gap as small as 1.0 eV when the nitrogen composition is about 2%. Indium can also be added to the alloy to increase lattice matching to GaAs and Ge. These properties are advantageous for developing a highly-efficient, multi-junction solar cell. However, poor GaAsN cell properties, such as low open-circuit voltage, have led to inadequate performance. Deep-level transient spectroscopy of p-type GaAsN has identified an electron trap having an activation energy near 0.2 eV and a trap density of at least 1016 cm-3. This trap level appears with the addition of small amounts of nitrogen to GaAs, which also corresponds to an increased drop in open-circuit voltage.

Several problems exist with current methods used to align DNA sequences for comparative sequence analysis. Most dynamic programming algorithms assume that conserved sequence elements are collinear. This assumption appears valid when comparing orthologous protein coding sequences. Functional constraints on proteins provide strong selective pressure against sequence inversions, and minimize sequence duplications and feature shuffling. For non-coding sequences this collinearity assumption is often invalid. For example, enhancers contain clusters of transcription factor binding sites that change in number, orientation, and spacing during evolution yet the enhancer retains its activity. Dotplot analysis is often used to estimate non-coding sequence relatedness. Yet dot plots do not actually align sequences and thus cannot account well for base insertions or deletions. Moreover, they lack an adequate statistical framework for comparing sequence relatedness and are limited to pairwise comparisons. Lastly, dot plots and dynamic programming text outputs fail to provide an intuitive means for visualizing DNA alignments.

Thin hydrogenated amorphous silicon (a-Si:H) layers deposited by hot-wire chemical vapor deposition (HWCVD) are investigated as emitters and back-surface-field (BSF) contacts to make silicon heterojunction solar cells on p-type crystalline silicon wafers. A common requirement for excellent emitter and BSF quality is minimization of interface recombination. Best results require immediate a Si:H deposition and an abrupt and flat interface to the c-Si substrate. We obtain record 16.9% and 14.8% efficiencies on p-type planar float-zone (FZ) and Czochralski (CZ) silicon substrates, respectively, with HWCVD a-Si:H(n) emitters and Al-BSF contacts. Initial efforts with p-type HWCVD Si thin films as the BSF have yielded 12.5% efficiency on p type CZ-Si.