A Flexible Simple Thermostat for Small Objects and the Range of 100 to 400 K

A flexible, inexpensive thermostat for the temperature range 100 to 400 K is described. Liquid nitrogen is the coolant and a gas serves as transfer medium. The temperature can be set to better than 1 K and is held there within (1/2) K by an electronic control system. The relatively small working volume of the order of 10 cm^3 allows quick changes of temperature, a desirable feature in typical semiconductor experiments

A flexible, simple thermostat for small objects and the temperature range of 100 deg K to 400 deg K

Thermostat for small objects with temperature range of 100 to 400

Space Station Freedom Solar Array design development

The Space Station Freedom Solar Array Program is required to provide a 75 kW power module that uses eight solar array (SA) wings over a four-year period in low Earth orbit (LEO). Each wing will be capable of providing 23.4 kW at the 4-year design point. Lockheed Missles and Space Company, Inc. (LMSC) is providing the flexible substrate SAs that must survive exposure to the space environment, including atomic oxygen, for an operating life of fifteen years. Trade studies and development testing, important for evolving any design to maturity, are presently underway at LMSC on the flexible solar array. The trade study and development areas being investigated include solar cell module size, solar cell weld pads, panel stiffener frames, materials inherently resistant to atomic oxygen, and weight reduction design alternatives

Search for Exotic Muon Decays

Recently, it has been proposed that the observed anomaly in the time distribution of neutrino induced reactions, reported by the KARMEN collaboration, can be interpreted as a signal from an exotic muon decay branch mu+ to e+ X. It has been shown that this hypothesis gives an acceptable fit to the KARMEN data if the boson X has a mass of m_X=103.9MeV/c^2, close to the kinematical limit. We have performed a search for the X particle by studying for the first time the very low energy part of the Michel spectrum in mu+ decays. Using a HPGe detector setup at the muE4 beamline at PSI we find branching ratios BR(mu+ to e+ X)<5.7e-4 (90% C.L.) for most of the region 103MeV/c^2<m_X<105MeV/c^2.Comment: 9 page

Noise and Equivalent Circuit of Double Injection

Measurements of the high‐frequency noise of a silicon double‐injection diode result in 〈i^2〉 = α⋅4kT(1/r)Δf with α=1.04 and in agreement with the literature. A new interpretation demands Nyquist noise with α≡1 in these devices at high frequencies. This is in accord with an equivalent circuit derived for the double‐injection process. Speculations are made on the general validity of Nyquist noise in nonlinear devices at high frequencies. In addition, generation‐recombination noise is suggested as the prime source of the low‐frequency noise

Collision damping in the pi 3He -> d'N reaction near the threshold

We present a simple quantum mechanical model exploiting the optical potential approach for the description of collision damping in the reaction pi 3He -> d'N near the threshold, which recently has been measured at TRIUMF. The influence of the open d'N -> NNN channel is taken into account. It leads to a suppression factor of about ten in the d' survival probability. Applications of the method to other reactions are outlined.Comment: RevTeX4, 14 pages, 3 Postscript figures, uses epsfig.sty, to appear in Phys.Rev.

An Updated Checklist to the Non-biting Midges (Chironomidae) of Illinois

The Chironomidae, or non-biting midges, of Illinois have been untreated since the early 20th century, and the high level of taxonomic flux in the family necessitates an update, particularly for a group with importance as bio-indicators of freshwater ecosystem health. Herein, 181 species of Chironomidae in 76 genera are recorded from the state of Illinois. Each species entry is annotated with the first Illinoisan record of the species. Two genera, Brillia Kieffer, 1913 and Prodiamesa Kieffer, 1906, are recorded for the first time from Illinois, as are three species: Xenochironomus xenolabis (Kieffer in Thienemann and Kieffer, 1916) (Chironominae); Brillia flavifrons (Johannsen, 1905) (Orthocladiinae); and Prodiamesa olivacea (Meigen, 1818) (Prodiamesinae)

Three-body decay of the d* dibaryon

Under certain circumstances, a three-body decay width can be approximated by an integral involving a product of two off-shell two-body decay widths. This ``angle-average'' approximation is used to calculate the $\pi NN$ decay width of the $d^*(J^\pi=3^+, T=0)$ dibaryon in a simple $\Delta^2$ model for the most important Feynman diagrams describing pion emissions with baryon-baryon recoil and meson retardation. The decay width is found to be about 0.006 (0.07, 0.5) MeV at the $d^*$ mass of 2065 (2100, 2150) MeV for input dynamics derived from the Full Bonn potential. The smallness of this width is qualitatively understood as the result of the three-body decay being ``third forbidden''. The concept of $\ell$ forbiddenness and the threshold behavior of a three-body decay are further studied in connection with the $\pi NN$ decay of the dibaryon $d'(J^\pi=0^-, T=0 or 2)$ where the idea of unfavorness has to be introduced. The implications of these results are briefly discussed.Comment: 15 pages, RevTeX, two-column journal style, six figure

Does the quark cluster model predict any isospin two dibaryon resonance?

We analyze the possible existence of a resonance in the $J^P=0^-$ channel with isospin two by means of nucleon-$\Delta$ interactions based on the constituent quark model. We solve the bound state and the scattering problem using two different potentials, a local and a non-local one. The non-local potential results to be the more attractive, although not enough to generate the experimentally predicted resonance.Comment: 9 pages in Latex (revtex), 2 eps figures available under reques