There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

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

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

In the last 10 years the field of molecular diagnostics has witnessed an explosion of interest in the use of nanomaterials in assays for gases, metal ions, and DNA and protein markers for many diseases. Intense research has been fueled by the need for practical, robust, and highly sensitive and selective detection agents that can address the deficiencies of conventional technologies. Chemists are playing an important role in designing and fabricating new materials for application in diagnostic assays. In certain cases assays based upon nanomaterials have offered significant advantages over conventional diagnostic systems with regard to assay sensitivity, selectivity, and practicality. Some of these new methods have recently been reviewed elsewhere with a focus on the materials themselves or as subclassifications in more generalized overviews of biological applications of nanomaterials.1-7 We intend to review some of the major advances and milestones in the field of detection systems based upon nanomaterials and their roles in biodiagnostic screening for nucleic acids, * To whom correspondence should be addressed. Phone: 847-4913907. Fax: 847-467-5123. E-mail: chadnano@northwestern.edu. Nathaniel L. Rosi earned his B.A. degree at Grinnell College (1999) and his Ph.D. degree from the University of Michigan (2003), where he studied the design, synthesis, and gas storage applications of metal−organic frameworks under the guidance of Professor Omar M. Yaghi. In 2003 he began postdoctoral studies as a member of Professor Mirkin’s group at Northwestern University. His current research focuses on the rational assembly of DNA-modified nanostructures into larger-scale materials.

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Nanostructures in Biodiagnostics

Nanoscale vacuum channel transistor

Ion-sensitive field-effect transistors (ISFETs) with a honeycomb nanowire (HCNW) structure have been fabricated on a silicon-on-insulator wafer. The HCNW ISFET shows lower threshold voltage, lower subthreshold swing, higher drain current, and lower variability than the conventional nanowire device. Improved electrical characteristics are mainly due to the increased effective channel width and enhanced current drivability. The HCNW structure also exhibits improved current sensitivity in its pH response. These results suggest that the HCNW structure is promising for enhancing device performance and realizing sensors with high sensitivity.

Improved Electrical Characteristics of Honeycomb Nanowire ISFETs

Surface analysis and electrochemistry of a robust carbon-nanofiber-based electrode platform H 2 O 2 sensor

A Monte Carlo sensitivity analysis is used to build a plasma chemistry model for octacyclofluorobutane (c‐C4F8) which is commonly used in dielectric etch Experimental data are used both quantitatively and qualitatively to analyze the gas phase and gas surface reactions for neutral radical chemistry The sensitivity data of the resulting model identifies a few critical gas phase and surface aided reactions that account for most of the uncertainty in the CF2 and CF radical densities Electron impact dissociation of small radicals (CF2 and CF) and their surface recombination reactions are found to be the rate-limiting steps in the neutral radical chemistry The relative rates for these electron impact dissociation and surface recombination reactions are also suggested The resulting mechanism is able to explain the measurements of CF2 and CF densities available in the literature and also their hollow spatial density profiles

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Monte Carlo sensitivity analysis of CF2 and CF radical densities in a c‐C4F8 plasma

Regular three-dimensional (3-D) arrays of crystalline SnO2-In2O3 nanowires were produced on m-sapphire using a gold catalyst-assisted vapor-liquid-solid growth process. The growth characteristics at multiple growth conditions were analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), x-ray photoemission spectroscopy (XPS), and Rutherford backscattering spectroscopy (RBS) to evaluate the functional dependence of nanowire structure and composition on growth parameters such as temperature and source composition. The results indicate that nanowires of mixed composition are not possible from the catalytic clusters; rather, a mixture of indium and tin oxide wires are formed in the range of conditions investigated here.

Meyya Meyyappan

Papers

Nanoscale vacuum channel transistor

Improved Electrical Characteristics of Honeycomb Nanowire ISFETs

Surface analysis and electrochemistry of a robust carbon-nanofiber-based electrode platform H 2 O 2 sensor

Monte Carlo sensitivity analysis of CF2 and CF radical densities in a c‐C4F8 plasma

Indium and tin oxide nanowires by vapor-liquid-solid growth technique