The technique of coupling two loudspeakers to obtain a signal proportional to the velocity of the cone is known. The sound at a distant point from a loudspeaker is related to the diaphragm displacement. Since the indu...The technique of coupling two loudspeakers to obtain a signal proportional to the velocity of the cone is known. The sound at a distant point from a loudspeaker is related to the diaphragm displacement. Since the induced e.m.f is proportional to the voice coil velocity,measurement of induced e.m.f enables us to obtain the displacement of the cone and hence we can plot the SPL curve for a loudspeaker. This method has some limitations in that it is particularly applicable only when one is interested in using the output of the second speaker used as a sensor in some further applications.展开更多
Values of the second thermodynamic dissociation constant pK2 of the protonated form of monosodium 1,4-piperazinediethanesulfonate (PIPES) have been determined at twelve different temperatures in the temperature range ...Values of the second thermodynamic dissociation constant pK2 of the protonated form of monosodium 1,4-piperazinediethanesulfonate (PIPES) have been determined at twelve different temperatures in the temperature range from (278.15 to 328.15) K including the body temperature 310.15 K by measurement of the electromotive-force for cells without liquid junction of the type: Pt (s), H2 (g), 101.325 kPa|Na-PIPES (m1) + Na 2-PIPES (m2) + NaCl (m3)|AgCl (s), Ag (s), where m1, m2 and m3 indicate the molalities of the corresponding species at 1 atm = 101.325 kPa in SI units. The pK2 values for the dissociation of Na-PIPES are represented by the equation: pK2 = -1303.76/T + 48.369 - 6.46889 lnT with an uncertainty of ± 0.001. The values of pK2 for Na-PIPES were found to be 7.1399 ± 0.0004 at 298.15 K and 7.0512 ± 0.0004 at 310.15 K, respectively, and indicate that this buffer would be useful as pH standard in the range of physiological application. Standard thermodynamic quantities for the acidic dissociation process of Na-PIPES have been derived from the temperature coefficients of the pK2. These values are compared with those of structurally related N-substituted PIPERAZINE and TAURINE at 298.15 K.展开更多
文摘The technique of coupling two loudspeakers to obtain a signal proportional to the velocity of the cone is known. The sound at a distant point from a loudspeaker is related to the diaphragm displacement. Since the induced e.m.f is proportional to the voice coil velocity,measurement of induced e.m.f enables us to obtain the displacement of the cone and hence we can plot the SPL curve for a loudspeaker. This method has some limitations in that it is particularly applicable only when one is interested in using the output of the second speaker used as a sensor in some further applications.
文摘Values of the second thermodynamic dissociation constant pK2 of the protonated form of monosodium 1,4-piperazinediethanesulfonate (PIPES) have been determined at twelve different temperatures in the temperature range from (278.15 to 328.15) K including the body temperature 310.15 K by measurement of the electromotive-force for cells without liquid junction of the type: Pt (s), H2 (g), 101.325 kPa|Na-PIPES (m1) + Na 2-PIPES (m2) + NaCl (m3)|AgCl (s), Ag (s), where m1, m2 and m3 indicate the molalities of the corresponding species at 1 atm = 101.325 kPa in SI units. The pK2 values for the dissociation of Na-PIPES are represented by the equation: pK2 = -1303.76/T + 48.369 - 6.46889 lnT with an uncertainty of ± 0.001. The values of pK2 for Na-PIPES were found to be 7.1399 ± 0.0004 at 298.15 K and 7.0512 ± 0.0004 at 310.15 K, respectively, and indicate that this buffer would be useful as pH standard in the range of physiological application. Standard thermodynamic quantities for the acidic dissociation process of Na-PIPES have been derived from the temperature coefficients of the pK2. These values are compared with those of structurally related N-substituted PIPERAZINE and TAURINE at 298.15 K.
