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(Corresponding to U.S. Patent No. 3,663,346)

Honeycomb cores formed of tubule sections bounded orthogonally by plane facings are described. The tubule sections are defined as being formed of minimal surface elements that orthogonally intersect all of the surfaces of a kaleidoscopic cell at least once. In other words, the tubule sections are broken into elements for definition purposes. The elements are defined as minimal surface elements, i.e., elements that have a mean curvature that is equal to zero at all points on their surface. These elements are further defined inside an imaginary kaleidoscopic cell in that they orthogonally intersect all surfaces of an imaginary kaleidoscopic cell at least once. The tubule sections are smoothly interconnected to form honeycomb core structures that have no internal discontinuities.

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EXPANDABLE SPACE FRAMES

NASA Case No. ERC-10365

Great Britain, West Germany,
Belgium, Sweden, Japan, Argentina,
Canada, Netherlands, Mexico,
Switzerland, France, Italy,
Australia, India

Address inquiries to:
NASA Pasadena Office
Attn: Patent Counsel
Mail Code: 180-601
4800 Oak Grove Drive
Pasadena, CA 91103
U.S.A.

(Corresponding to U. S. Patent No. 3,757,476)

Expandable space-frames formed of a plurality of hinge joint assemblies and struts are reported in this invention. The spaceframes are utilized in various types of structures. They can form a basic building structure or can be utilized in a planar manner to form the floors and walls of a structure. They can be utilized in space to define a structure such as a manned orbiting laboratory.

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ELECTRON MICROSCOPE APERTURE SYSTEM

NASA Case No. ARC-10448-1

Canada, France, Japan, Germany,
Great Britain, Netherlands

Address inquiries to:
Ames Research Center
Attn: Patent Counsel
Mail Code: 200-11A
Moffett Field, CA 94035
U.S.A.

(Corresponding to U.S. Patent No. 3,847,689)

An electron microscope is described, which includes an electron source, a condenser lens having either a circular aperture for focusing a solid cone of electrons onto a specimen or an annular aperture for focusing a hollow cone of electrons onto the specimen, and an objective lens with an annular objective aperture, for focusing electrons passing through the specimen onto an image plane. The invention also entails a method of making the annular objective aperture, using electron imaging, electrolytic deposition, and ion etching techniques.

INFRARED TUNABLE LASER

NASA Case No. ARC-10463

Belgium, Canada, France,
Germany, Japan, Great
Britain, Netherlands

Address inquiries to:
Ames Research Center
Attn: Patent Counsel
Mail Code: 200-11A
Moffett Field, CA 94035
U.S.A.

(Corresponding to U.S. Patent No. 3,753,148)

The invention relates to laser apparatus for providing an intense source of coherent laser radiation which is tunable from the visible wavelengths through the infrared wavelengths. It can be used in absorption spectroscopy and in the detection and monitoring of pollution in the atmosphere. Selected radiation of the tunable laser is passed through the non-linear mixing crystal causing it to develop radiation of a third wavelength which is transmitted out of the optical cavity through the third reflector.

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POLYIMIDE FOAM FOR THERMAL INSULATION

AND FIRE PROTECTION

NASA Case No. ARC-10464-1

Canada, Great Britain, France,
West Germany, Japan, Italy,
Switzerland

Address inquiries to:
Ames Research Center
Attn: Patent Counsel
Mail Code: 20011A
Moffett Field, CA 94035
U.S.A.

(Corresponding to U.S. Patent No. 3,772,216)

In the preparation of polyimide foams by the reaction of polyisocyanates and polyfunctional aromatic acid derivatives, flame retardant foamed products of improved cell quality, friability, and resiliency are obtained by conducting the reaction in the presence of an alkanolamine, such as 1-hydroxyethyl-2-heptadecenyl glyoxalidine. Another aspect of the invention resides in the finding that

6 lbs/cu ft can be obtained by, employing in the reaction at least 2% by weight of silozane-glycol copolymer as a surfactant which acts as a specific density control agent. A further feature of the invention is the production of polyimide foams into which reinforcing fibers such as silicon dioxide and carbon fibers may be incorporated.

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