Transmission hysteresis

Because these analysers do not employ magnets, peak switching for selected ion monitoring can be done more quickly without hysteresis effects, which makes this system ideal for depth profiling, where it is necessary constantly to switch among masses. These instruments do have the disadvantage of loss of transmission and mass... 

In these polymeric species, the M,AT2-1,2,4-triazole linkage is rigid, and allows an efficient transmission of cooperative effects. Consequently, abrupt ST with broad thermal hysteresis loops have been observed [26, 32-34]. The absorption spectra of these compounds show a broad band at 520 nm corresponding to the Aig Trg d-d transition in the LS state whereas no band is found in the visible region in the HS state, the 5T2g-5Eg transition being located around 850 nm [7a]. The ST is thus accompanied by a thermochromic effect, purple (LS) and white (HS). These characteristics make these compounds potential candidates for practical applications, e.g. thermal display devices [7, 8, 17]. Such behaviour has been observed, for example, in the compound [Fe(4-amino-l,2,4-triazole)3](NC>3)2 [32] whose SCO is associated with a hysteresis loop of width 35 K, centred above room temperature [8]. 

An extremely unusual power dependence has been observed in the cooperative upconversion luminescence of Yb -doped Cs3Lu2Br9 and related systems [57-61]. As illustrated by the 7.5 K power-dependence data in Fig. 14a, b, increasing the excitation power from the low-power excitation limit results in a sharp jump in both VIS and NIR luminescence intensities at a certain critical power. Reversing the direction of the power sweep also results in a sharp jump on the return path, but this jump occurs at a lower power than the forward jump, resulting in a hysteresis behavior with a distinct region of bistability. Monitoring the transmission of the laser beam shows that the absorption of the sample also increases and decreases at these same critical powers (Fig. 14a, inset) [62]. The properties of this jump are clearly dependent upon temperature, with smaller jumps observed at lower excitation powers as the temperature is elevated (Fig. 14). 

Fig. 14 a, b. Power and temperature dependence of a the visible cooperative luminescence b the NIR downconversion luminescence in 10% Yb + Cs3Lu2Br9 excited at 10,591 cm plotted on linear axes. These data show distinct hystereses, the properties of which are temperature dependent. Inset 10 K laser transmission, which also shows hysteresis behavior. Adapted from [62]... 

The nanoparticles have been characterized by X-ray diffraction and transmission electron microscopy. Both MnO and NiO nanoparticles exhibit supermagnetism, accompanied by magnetic hysteresis below the blocking temperature (7b). The 7b increases with the increase in particle size in the case of NiO, and exhibits the reverse trend in the case of MnO. 

If the distortion of the interface by the higher harmonics generated can be neglected as a higher-order effect, the interface vibration is sinusoidal with the excitation frequency. Its displacement amphtude ao is determined by the stress and displacement continuity of the waves of fundamental frequency at the interface. If the transmission of the fundamental frequency shows no hysteresis relative to the interface vibration, we get the result ao=fiBi/k, fiBi = 2 /fi] — e. Here k=colVi is the wavenumber and Vl is the compressional sound velocity in the aluminum plates [10]. The strain amphtude in the interface is the ratio of Oq to the thickness of the interface, i.e., the interface strain amphtude is directly proportional to bi. 

Fig. 7.17 Hysteresis in the p-c isotherms (c) and hydrogen concentration dependence of the electrical resistivity (a) and transmission (b) ofYHy during a hydrogen loading (filled circles) - unloading cycle (open circles). The giant hysteresis (factor 10 ) in...

Figure 10.13 shows experimental setup for the optical characteristic measurement of PMNT ceramics [133]. The size of PMN-PT ceramic sample was 5 mm X 2 mm x 1 mm for length x width x thickness. Ti/Pt/Au layers were sputtered on both surfaces of the ceramics as electrodes. Two collimators were used to collimate the incident beam and receive the transmission beam. The output beam was detected by using an optical spectrometer and phase demodulation. Because the PMN-PT electro-optic ceramics have a large refractive index, i.e., n = 2.465, the ceramic samples could be considered as a Fabry-Perot (FP) resonator, which can be used to measure the electric hysteresis and thermo-optic coefficient. The applied voltage generated a transverse electro-optic effect for the transmission light beam. 

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