Study of the quasi-periodic effect in the design of reflectarray antennas

2016 ◽  
Author(s):  
Tong Liu ◽  
Maokun Li ◽  
Fan Yang ◽  
Shenheng Xu
Keyword(s):  
Periodic Effect

The reflection of electrons from standing light waves

1933 ◽  
Vol 29 (2) ◽  
pp. 297-300 ◽  
Author(s):  
P. L. Kapitza ◽  
P. A. M. Dirac
Keyword(s):  
Scattered Radiation ◽  
Photographic Plate ◽  
Standing Waves ◽  
Main Interest ◽  
Light Waves ◽  
Direct Scattering ◽  
Periodic Effect ◽  
Colour Photography ◽  
Colour Effect

It is well known that a beam of light falling on a reflecting mirror forms standing waves. This effect has been very beautifully made use of in Lippmann's colour photography process. The standing light waves, in this case, produce a periodic effect in the emulsion of the photographic plate which, when developed, scatters light and produces a similar colour effect. Instead of using a beam of light, it would seem possible to scatter electrons from the emulsion and obtain a reflection of electrons similar to that of a space grating. But it seemed to us that it would be of much greater interest to consider an experiment in which electrons are reflected from the standing waves of light. The direct scattering of free electronic waves by light has strictly never been observed, and it was thought possible that by this method, owing to the interference of the electrons and to the fact that the scattered electrons are focussed to one spot, the magnification of the phenomenon would be sufficient to make it observable. From the theory developed below, it will be seen that the experiment is just on the verge of possibility, and would be very difficult to carry out. The main interest of the experiment would come from the possibility of observing stimulated scattered radiation which up to the present has never been verified experimentally.

Periodic Effect of Pressure and Temperature on Flow Phenomena in Porous Media

2004 ◽  
Author(s):  
I. Lakatos ◽  
J. Tóth ◽  
J. Lakatos-Szabó ◽  
B.H. Rayes ◽  
M. Hlatki ◽  
...  
Keyword(s):  
Porous Media ◽  
Effect Of Pressure ◽  
Periodic Effect ◽  
Flow Phenomena

Optimum Error Separation Technique for In-Situ Straightness Measurement in Diamond Turning

2000 ◽  
Author(s):  
Jianming Yu ◽  
C. James Li
Keyword(s):  
Sampling Interval ◽  
Diamond Turning ◽  
New Method ◽  
Separation Technique ◽  
Error Separation ◽  
Periodic Effect ◽  
The One ◽  
In Situ Metrology ◽  
Metrology System

Abstract In diamond turning, measurement of a workpiece without removing it from the machine tool needs an in-situ metrology system and an error separation technique. The traditional methods for error separation have their limitation in straightness measurement. In this paper, a thorough analysis is given for the non-periodic effect on error separation, and a new method is described to overcome the limitation in straightness measurement for short workpiece. The new method enables the use of a sampling interval smaller than the one permitted by the traditional techniques and gives more detailed information about the measured workpiece profile. Consequently, it is suitable for the in-situ measurements of short workpieces in diamond turning.

scholarly journals Poliomyelitis in Auckland, 1947–1949. An epidemiological study

1950 ◽  
Vol 48 (1) ◽  
pp. 96-120 ◽  
Author(s):  
A. W. S. Thompson
Keyword(s):  
Urban Areas ◽  
Local Density ◽  
Age Groups ◽  
Inverse Correlation ◽  
Periodic Effect ◽  
Significant Difference ◽  
Lower Severity ◽  
Low Incidence ◽  
Rural Dwellers ◽  
Sanitary Conditions

(a) This paper is a study of a poliomyelitis epidemic in the Central Auckland Health District which commenced in November 1947, and by the end of April 1949 had produced 345 cases in a population of about 350,000.(b) Incidence per 10,000 reached 8·0 in the city, 15·4 in the country districts, and 21·5 in certain urban areas lying between city and country.(c) In general, incidence was inversely related to population density. Abnormally high incidences in some urban areas was attributed to influx of rural dwellers in recent years. Unusually low incidence in one city area may have been related to the periodic effect of race meetings in increasing the local density.(d) The three previous Auckland epidemics showed a successively declining incidence, and were linked by periods of grumbling activity. The present epidemic was preceded by a lull, and its toll has approached that of the 1916 epidemic. It is probable that a new cycle has begun which will imitate the first, but on a lower scale.(e) Spot maps showed that the disease was already widespread before the first positive cases revealed its presence. Some ebb and flow, but no actual movement from one area to another, occurred during its course. An interesting feature was the comparative rarity of cases in the neighbourhood of the city's sewage-polluted bathing beaches.(f) An inverse correlation was noted between the ratios of ‘suspect’ to positive cases established in a previous inquiry, and the incidence of cases with paralysis or paresis in various age/sex groups. High ratios indicated lower severity.(g) It was estimated that by the end of April 1949, all boys 10–15 years in Auckland had been affected by poliomyelitis, either ‘suspect’ or positive. Less than half the girls of this age had been affected. Estimates are given for the other age groups.(h) Families of cases showed no significant difference in composition from the average in the area.(i) No correlation, whether inverse or direct, was found between sanitary conditions in schools and the incidence of positive cases.(j) The cycle of poliomyelitis in the community is discussed in the light of these findings.

scholarly journals Periodic solution to general conduction problems

2013 ◽  
Vol 17 (5) ◽  
pp. 1494-1496
Author(s):  
Gui Mu ◽  
Zhengde Dai ◽  
Jun Liu ◽  
Jie Fu
Keyword(s):  
Periodic Solution ◽  
Function Method ◽  
Solution Process ◽  
Energy Localization ◽  
Periodic Effect ◽  
Hyperbolic Cosine ◽  
Cosine Functions

In this paper, we present a modified exp-function method, where hyperbolic cosine and cosine functions are used. The hyperbolic cosine functions are responsible for energy localization while cosine functions reveal the periodic effect. A general conduction problem is used as an example to illustrate the solution process.

scholarly journals The contribution of galenics to patients’ sensory perception of nasal sprays after nasal surgery – data from a prospective randomized, controlled, double-blind, cross-over, multi-centre study

2021 ◽  
Author(s):  
Christoph Bergmann ◽  
Jennifer Lander ◽  
Lea Radtke ◽  
Laura England ◽  
Jaswinder Singh ◽  
...  
Keyword(s):  
Nasal Spray ◽  
Nasal Surgery ◽  
Double Blind ◽  
Multi Centre Study ◽  
Entire Study ◽  
Nasal Sprays ◽  
Periodic Effect ◽  
Physical Examinations ◽  
Sum Scores ◽  
The Eu

Abstract Introduction:Postoperative care after nasal surgery is commonly achieved with nasal sprays. The current study compared two decongesting, wound healing nasal sprays in patients after nasal surgery in order to investigate their sensoric perception. One of the sprays presented a new galenic formulation (nasic® neo, Cassella-med GmbH & Co. KG).Methods:Using a cross-over design, patients who had undergone nasal surgery applied two different nasal sprays during two treatment periods of 4 days each, interrupted by 3 days wash out period. Sensoric perception of the nasal sprays was assessed with the nasal-spray-sensoric-scale. Throughout the study, nasal obstruction was evaluated by patients, and physical examinations, measurements of vital parameters and rhinoscopic examinations were carried out by investigators. Adverse events were documented during the entire study, and following treatment, patients judged the overall preference, efficacy and tolerability of both products.Results:Overall, no significant differences in sum scores of the assessments of the nasal-spray-sensoric-scale were observed between treatments. Significant periodic effect observed during the cross-over study limited the overall analysis. Nevertheless, it could be shown that significantly more patients preferred the new galenics nasal spray compared to the comparator spray (57.1% vs. 34.7%; p=0.031). Further, 10% more patients rated the efficacy of new galenics as ‘good’ to ‘very good’ compared to the comparator. Importantly, a subgroup population of patients with more pronounced signs of inflammation present at screening evaluated the sensoric perception of new galenics significantly better (p=0.033) compared to the comparator. Within this subgroup, no periodic effect was observed. The application of both nasal sprays was shown to be safe and well-tolerated.Conclusion:The current study showed that the overall sensoric perception of both nasal sprays was evaluated comparably well in patients after nasal surgery and that overall, the application of the new galenics nasal spray was preferred by significantly more patients compared to the comparator nasal spray. Patients with marked nasal abnormalities may have a greater benefit from the contribution of galenics as significant differences in the sensoric evaluation by the nasal-spray-sensoric-scale in favour of the new galenics product were shown for this subgroup.Trial registration: The current study was registered in the EU Clinical Trials Register with the EudraCT No: 2019-004936-52.

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