RESUMEN
The helical crystal structure in optically active media acts as the natural micro-solenoids for the electromagnetic waves passing through them, producing the longitudinal magnetic field in the direction of the axis of helices. Magnetic flux through the helical structure is quantized. The Berry phase is induced by rotation of the electrons around the helical structure. Optical rotation is related to the difference in the accumulative Berry phase between the right-, and the left-circularly polarized waves, which is proportional to the magnetic flux through the helical structure, according to the Aharonov-Bohm effect. The optical activity is the natural Faraday effect and the natural Aharonov-Bohm effect.
Asunto(s)
Luz , Modelos Teóricos , Refractometría/métodos , Dispersión de Radiación , Simulación por ComputadorRESUMEN
An experiment was proposed to probe quantum effects on optical activity. The helical structures in optically active media act as natural microsolenoids for the electromagnetic waves passing through them, which produces a longitudinal magnetic field in the axis of helices. Magnetic flux through a helical crystal structure is quantized. A high number of quanta in the rotatory power was probed in the optical activity of alpha-quartz.
RESUMEN
Spectroscopic measurements were used to monitor the optical interference of ordinary (o-ray) waves with extraordinary (e-ray) waves by incidence of plane-polarized light and transmission through piezoelectriccrystals (alpha-quartz, LiNbO3, and LiTaO3). This observation confirms that the rotations of the vibration planes of the o- and e-ray waves originate from the dynamic gratings induced by the electric field of the incident light. This is a self-modulation process of the polarized incident light in piezoelectric crystals.
RESUMEN
OBJECTIVE: To study the curative effect of pulsed Nd:YAG laser on early root-surface caries in senile patients. METHODS: Teeth with early root-surface caries removed from patients aged over 60 were irradiated with different energy output and sealant and observed under scanning electron microscope. RESULTS: Surface layer on early root-face caries were seen to be honeycomb or nibbled before irradiation, melted after irradiated by Nd:YAG laser,and with a smooth surface of the lesion after sealed. CONCLUSION: Early root-surface caries sealed with light-cured sealant after pulsed Nd:YAG laser irradiation is a safe and effective therapy.
RESUMEN
131 cases of epidemic hepatitis from two villages in Xinjiang, were admitted to the provisional infectious diseases hospital from February to April 1987. In 125 (95%) patients neither anti-HAV IgM nor anti-HBc IgM were positive. 118 (90%) were drinking water from a local stream of the Hotan River. The study was conducted on 125 patients aged from 5 to 90 years, with a mean of 26.4 years. There were slightly more males than females, a ratio of 1.5 to 1. The incubation period was roughly estimated to be 17 to 37 days (mean 24.8 days). All subjects were jaundiced. 12 patients (including 6 pregnant women) had cholestatic symptoms. Except one woman who died of postpartum bleeding, all patients ran a benign course without fulminant hepatic failure. Pathologic changes of liver biopsies from 35 cases included lobular damage and inflammation, ballooned hepatocytes with clear cytoplasm and delineated cell membrane which were named "clear cell". There were cholestasis of different degrees in the acute icteric stage and fatty changes in the convalescent stage. It was seen under the electron microscope that the livers of 8 cases had neither tubular structure nor sponge-like inclusions, but had nuclear changes including curled edge of nuclear membrane and nuclear heterochromatin condensed in masses. Liver biopsies were repeated in 7 cases followed up for 6-13 months, and hepatohistology was normal in 5. Of the other two cases there was one of each.
