Abstract: Hollow fibers having an internal diameter from 1 nm to 100 nm can be produced by coating degradable materials with nondegradable materials and then degrading the degradable materials. The hollow fibers are useful in separation technology, catalysis, microelectronics, medical technology, materials technology or the clothing industry.

Abstract: Gases can be selectively detected by utilization of an infrared (IR) absorption photometer via their specific absorption in the IR range. Known instruments are generally rather expensive, are of considerable size, require careful treatment and as a rule can be operated by skilled personnel only. The microstructured IR absorption photometer of the present invention is developed for (quasi-) continuously controlling a gaseous stream, the photometer being a single-piece shaped part manufactured as a microstructured body. The photometer is compact and robust, suitable for portable instruments and can be manufactured at low cost and in large numbers. The photometer can be made of metal and can be used even at an increased temperature. A flashlight lamp serves as an IR radiation source and a lead selenide receiver as an IR radiation receiver. The pulse repetition frequency of the flashlight lamp is from 0.01 Hz to 10 Hz. The pulse interval preferably amounts to more than a thousand times the pulse duration.

Abstract: Gases can be selectively detected by the utilization of a infrared spectrometer via their specific absorption in the infrared spectral range. The sensor of the present invention is developed for continuously controlling a gaseous stream or a space filled with gas with the sensor being a single-piece shaped part manufactured as a microstructured body. The space filled with gas to be tested is between a mirror grating and entrance and exit slits for IR-radiation. The sensor is compact and robust, suitable for portable instruments, and can be manufactured at low cost and in large numbers. The sensor can also be made of metal and can be used even at an increased temperature. By using the sensor of the present invention, the safety of systems in which flammable, toxic or other gases are contained or may occur can be considerably increased in an economic manner.