Physical Sciences

A new type of lens design features broadband achromatic performance as well as telecentricity, using a minimum number of spherical elements. With appropriate modifications, the lens design form can be tailored to cover the range of response of the focal-plane array, from Si (400–1,000 nm) to InGaAs...

A paper describes direct numerical simulations (DNSs) of three-dimensional mixing-layer flows undergoing transition to turbulence; the mixing layers may or may not be laden with evaporating liquid drops. In contrast to most studies in this field, the...

An improved nozzle has been developed to replace nozzles used previously in an apparatus that generates a substantially unidirectional beam of molecules passing through a vacuum at speeds of several kilometers per second. The need to replace the previous nozzles arose from a complex set...

University of Illinois scientists have fabricated the world's smallest chain-mail fabric that consists of a network of small rings about 500 microns in diameter and even smaller links about 400 microns long. The rings and links are built upon a planar substrate and then released to create a flexible sheet that can bend along two...

A document describes a 5.5-m-diameter, helium-filled balloon designed for carrying a scientific payload having a mass of 44 kg for at least six days at an altitude of about 55 km in the atmosphere of Venus. The requirement for floating at nearly constant altitude dictates the choice of a...

Researchers at Massachusetts Institute of Technology (MIT) have created customizable hydrogel microparticles capable of identifying different biomolecules, disease monitoring, drug discovery, or genetic profiling. Each particle is equipped with a bar-coded ID and one or more probe regions that turn fluorescent when they detect...

A self-biased solar cell is available that provides improved conversion efficiency. Loss of carriers at the back surface of the battery is decreased, and open circuit voltage and quantum efficiency near a long wavelength are increased. View this technology here.

University of Wisconsin-Madison researchers have come one step closer to making fusion energy possible by showing that their magnetic plasma chamber, called a stellarator, can overcome a major barrier in plasma research by retaining the needed temperature for fusion to be possible. Past stellarators lose too much energy to reach the...

Purdue University researchers have created a handheld sensing system its creators liken to Star Trek's "tricorder" used to analyze the chemical components of alien worlds. The new portable system is an ultrafast chemical analysis tool that could be used for detecting everything from cancer in the liver to explosives residue...

Methods are available for the determination of building stability in the event of an earthquake. These methods involve the development of existing shaking table technology to allow more efficient characterization of structural properties. View this technology here. An approach accompanied by a comprehensive algorithm and...

Methods are available for the determination of building stability in the event of an earthquake. These methods involve the development of existing shaking table technology to allow more efficient characterization of structural properties. View this technology here.

Multiple-quantum-well (MQW) photodetectors of a proposed type would contain active regions comprising multiple superlattice subregions. These devices would have complex structures: The superlattice of each subregion would be designed for enhanced absorption of photons in a desired wavelength band...

A paper [Chem. Phys. Lett. 345, 295 (2001)] describes theoretical studies of excited electronic states of nitrogen molecules, with a view toward utilizing those states in synthesizing tetrahedral N4, or Td N4 — a metastable substance under consideration as a high-energy-density rocket...

A document discusses concepts for the design of an antenna to be deployed from a spacecraft for measuring the ambient electric field associated with plasma waves at a location within 3 solar radii from the solar photosphere. The antenna must be long enough to extend beyond the...

A report describes an improved high-voltage isolator for preventing electrical discharge along the flow path of a propellant gas being fed from a supply at a spacecraft chassis electrical potential to an ion thruster at a potential as high as multiple kilovolts. The isolator must survive launch...

Delta-doped, back-illuminated charge-coupled devices (CCDs) are used as detector arrays in high-performance double- focusing miniature mass spectrometers of Mattauch-Herzog design (described below). The uses of delta-doped CCD detector arrays eliminates the need for microchannel plates...