A system for underfilling in a chip package includes an underfill mixture that ameliorates the CTE mismatch that typically exists between a packaged die and a resin-impregnated fiberglass mounting substrate. The structure of the document is represented by a tree having one or more nodes. The output voltages can additionally be monitored during periods between stimulation pulses to improve the accuracy of the measurement, and is further beneficial in that such additional measurements are not perceptible to the patient. With a modular system, there are numerous variations for location and number of locks and the location of the crank assembly as well as other components. The silencer integrates several different silencing structures together, and, when mounted to the exhaust port of the vacuum cleaner, can considerably diminish the noise generated by the vacuum cleaner in operation. The Laval nozzle has a back pressure of the nozzle Po satisfying a formula, PoFhS, with respect to a oxygen-flow-rate FhS per hole of the Laval nozzle determined from the oxygen-flow-rate FS in a high carbon region in a peak of decarburization and a throat diameter Dt.