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.

/pdf/nanostructures-in-biodiagnostics-5553cs9yqw.pdf

Nanostructures in Biodiagnostics

https://www.mdpi.com/2079-6374/13/2/169/pdf?version=1675855071

Two-Dimensional Transition Metal Dichalcogenide Based Biosensors: From Fundamentals to Healthcare Applications

Supercapacitors prepared by printing allow a simple manufacturing process, easy customization, high material efficiency and wide substrate compatibility. While printable active layers have been widely studied, printable electrolytes have not been thoroughly investigated despite their importance. A printable electrolyte should not only have high ionic conductivity, but also proper viscosity, small particle size and chemical stability. Here, gel-polymer electrolytes (GPE) that are compatible with printing were developed and their electrochemical performance was analyzed. Five GPE formulations based on various polymer-conductive substance combinations were investigated. Among them, GPE made of polyvinylidene difluoride (PVDF) polymer matrix and LiClO4 conductive substance exhibited the best electrochemical performance, with a gravimetric capacitance of 176.4 F/g and areal capacitance of 152.7 mF/cm2 at a potential scan rate of 10 mV/s. The in-depth study of the in-plane solid-state supercapacitors based on various printed GPEs suggests that printable electrolytes provide desirable attributes for high-performance printed energy devices such as supercapacitors, batteries, fuel cells and dye-sensitized solar cells.

https://www.mdpi.com/1996-1944/14/2/316/pdf

Printable Gel Polymer Electrolytes for Solid-State Printed Supercapacitors.

This article discusses the self assembly of conjugated thiol molecular wires on Au(111) substrates and their charge transport studied by scanning tunneling microscopy and spectroscopy. Molecular resolution imaging of the conjugated thiols show that differences in their structure and inter molecular interactions result in an ordering on gold that is different from the hexagonal symmetry found in alkanethiols. Tunneling spectroscopy on the molecular wires provides information about their intrinsic electronic properties such as the origin of the observed conductance gap and asymmetry in the I–Vs. Further by concurrent topographic and tunneling spectroscopic studies on a conjugated thiol molecule self assembled with and without molecular order, we show that packing and order determine the response of the monolayer to various competing interactions and that the presence of molecular order is very important for reproducible transport measurements. Competing forces between the electric field, intermolecular interactions, tip-molecule physisorption and substrate-molecule chemisorption impact the transport measurements and its reliability. This study points to the fact that molecular electronic devices should be designed to be tolerant to such fluctuations and dynamics.

Effect of monolayer order and dynamics on the electronic transport of molecular wires

The performance of showerheads used in semiconductor processing applications has been examined over a wide range of Knudsen number and Reynolds number. Both computational fluid dynamics and direct simulation Monte Carlo techniques have been used to characterize the showerhead flow with the intent of developing correlations between the upstream velocity and the pressure drop across the showerhead. Empirical correlations developed to account for entrance effects and rarefaction are also examined. Recommendations are made concerning boundary conditions and, when appropriate, correlations for given pressures and flow rates.

Characterization of showerhead performance at low pressure

Nanoelectrode arrays (NEA) using 1-D nanomaterials as the electrode material have shown promise for biosensing applications. Vertical, freestanding, individual carbon nanofibers (CNFs) on patterned substrates constitute one example of NEA in the literature. The development of a biosensor system using this NEA first requires reliability studies prior to undertaking system integration with microfluidics and sample handling aspects. Here, we have investigated the effect of temperature and process conditions on the diameters and quality of the CNFs using atomic force microscopy (AFM). A Taguchi approach is employed to study the temperature effect in etched and unetched CNFs using AFM followed by a statistical analysis.

Meyya Meyyappan

Papers

Two-Dimensional Transition Metal Dichalcogenide Based Biosensors: From Fundamentals to Healthcare Applications

Printable Gel Polymer Electrolytes for Solid-State Printed Supercapacitors.

Effect of monolayer order and dynamics on the electronic transport of molecular wires

Characterization of showerhead performance at low pressure

Carbon Nanofiber Nanoelectrode Array: Effect of Process Conditions on Reliability