We demonstrate a duct muffler design that operates in the low-frequency range (<2000 Hz). The device contained pair of coupled annular Helmholtz resonators (HRs) and porous material stuffing. HRs were installed as side branches circular tube to avoid affecting ventilation. Porous materials employed form an asymmetric intrinsic loss HR enable achieve perfect sound absorption. An analytica...

The sperm-specific lactate dehydrogenase isoenzyme (LDH-X) appearing in electrophoresis between LDH-3 and LDH-4 is characteristic of human mature testis and spermatozoa. 1,21 Our previous studies have shown that detection of LDH-X by starch gel electrophoresis is quite suitable for forensic demonstration of semen from vaginal swabs. ) This communication reports the successful application of the...

We present mm-wave transmission as a complementary technique to characterize the properties of superconducting thin lms, obtaining information on both the real and imaginary part of the dielectric function. Examples are given to illustrate the strength of the technique to measure the response of dielectric materials and strati ed systems. We demonstrate the BCS-behavior of a conventional superc...