Iranian Light Source Facility (ILSF) RF system was conceptually designed based on ILSF requirements for a 3 GeV storage ring and 400 mA beam current at 500 MHz RF frequency. Considering the fact that cavity construction is simpler at 100 MHz and advantages of reducing frequency provided an alternative of 100MHz RF system to be explored for ILSF. After a thorough study on the effect of reducing RF frequency on electron beam, machine parameters and comparison of RF systems at both frequencies, the RF frequency was switched to 100 MHz. This paper presents these investigations and comparision leading to selecting the intended frequency. Furthermore, the electromagnetic and mechanical design for 100 MHz cavity are discussed.

The present study examined and analyzed citation frequency of ISI cited journals in organic chemistry for 2006. Number of citations to each reference within a given text was counted. By employing citation analysis based on frequency, the study posits the possibility of using citation frequency as a significant indicator in citation analysis researches based on citation count. A standard citation frequency analysis was used. It is a type of citation analysis focusing on citation frequency which is standard since both articles and citations were drawn from ISI indexed journals. Findings indicated that out of every 10 citations, 8 in-context citations belong to journals indexed in ISI. The distribution of this frequency is not normal. 3.5% of journals had the highest frequency while 40% had been repeated only once. A significant distinction between citations means and frequencies was discerned.

Several recent studies have suggested that young children who stutter tend to show depressed lexical performance relative to peers. Children who stutter was produced fewer total verbs and fewer different verbs than peers did, but these differences can not be attributed to increased general all-purpose verb use. Production of gap verbs was similar between the groups. The fact that the children who stutter produce significantly fewer verbs in their samples relative to peers and overall lexical diversity would be impacted by children who stutter producing fewer total and fewer different verbs. Likewise, if children who stutter produced fewer verbs than peers did, mean length utterance should be impacted, as well due to challenge in learning verbs in children it is important to assess lexical diversity in children. This research was a descriptive-analysis study and cases was selected in speech therapy clinics that conducted on 57 non-stutter children and 13 stutter children (primary school).Due to effects of some distortion factors on the frequency of core vocabulary, we have some exclusion criteria such as: neurological disorders, language disorder, color blinded and etc. The qualified subject entered the test. Then stutter's children implemented 100 words test to access in percent and severity of stuttering. Comparison of frequency of core vocabulary implemented by word articulation test and word perceptive test and we register frequency of perceptive and expressive vocabulary in noun, verb and adjective category. The result of this study reveal that mean of frequency of expressive and receptive vocabulary in noun category in stutter children is lesser than non stutter children. There was significant difference between stutter children and non stutter children in frequency of expressive and receptive vocabulary in noun category. The mean of frequency of expressive and receptive vocabulary in adjective category in stutter children is lesser than non-stutter children. There was not significant difference between stutter children and non stutter children in frequency of expressive and receptive vocabulary in adjective category. The mean of frequency of expressive and receptive vocabulary in verb category in stutter children is lesser than non-stutter children. But there was not significant difference between stutter children and non stutter children in frequency of expressive vocabulary in verb category. There was significant difference between stutter children and non stutter children in frequency of receptive vocabulary in verb category.: The results of this research indicate that frequency of expressive and receptive vocabulary in noun category in stutter children is significantly lesser than non-stutter children and stutter effect on frequency of expressive and receptive vocabulary in noun category. The frequency of expressive vocabulary in verb category in stutter children was not significantly lesser than non stutter children but frequency of receptive vocabulary in verb category in stutter children is significantly lesser than non stutter children and stutter effect on frequency of receptive vocabulary in verb category. The frequency of expressive and receptive vocabulary in adjective category in stutter children was not significantly lesser than non stutter children and stutter does not effect on frequency of expressive and receptive vocabulary in adjective category.

The writers of this paper introduce two kinds of linguistic frequency, type frequency and token frequency. Then, the effects of each kind of frequency on syntactic structures are analyzed. The token frequency effects are divided into two main types: conserving effect and reduction effect. The type frequency is mainly effective in syntactic productivity. The two effects of token frequency on syntax and their interaction with type frequency over time allows us to explain many situations in language that otherwise appear very arbitrary.

One of the most fundamental reservoir characteristics is the thickness. The analysis of thin bed tuning on seismic reflectivity has been studied extensively by Wides (1973) and Neidel and Pogiaggliomi (1977), who discussed the limits of seismic resolution. During the past decade, the industry has developed a plethora of new attributes in studying thin beds by employing spectral decomposition (Peyton et al., 1998; Partyka et al., 1999), and attributes which are obtained from it (Marfurt and Kirlin, 2001). Spectral decomposition refers to all methods that generate frequency spectrums consisting of amplitude spectrum, phase spectrum, change of phase with frequency and power spectrum in windows with the center of each time sample of a trace. These methods are used in studying geological features, thin beds, hydrocarbon reservoirs and noise attenuation. The most important of these methods are short time Fourier transform (STFT), continuous wavelet transforms, S-transform, Wigner-Ville distribution and matching pursuit decomposition. The result of a trace spectral decomposition is a time-frequency map.

The electric field in cavity accelerates charged particles and magnetic field of magnets changes the direction of these particles in cyclotrons. In order to establish the electric field inside the cavity, a noiseless radio frequency (RF) signal should be generated, amplified and sent to cavity. The resonant frequency of the cavity could be changed by temperature variation. Variation of resonant frequency will cause reflected power from the cavity. in this work the low level RF circuits with task of signal generation, phase and frequency Adjustment, cavity resonant frequency Adjustment, protection of the RF set from the reflected power and stability of RF system was designed.

In this paper, we introduce RF electron gun of Iranian Light Source Facility (ILSF) pre-injection system. Design, fabrication and low-power microwave tests results of the prototype RF electron gun have been described in detail. This paper also explains the tuning procedure of the prototype RF electron gun to the desired resonant frequency. The outcomes of this project brighten the path to the fabrication of the RF electron gun by the local industries

Identification of low-frequency shadows is very important in the sense that they are related to gas reservoirs. These low-frequency shadows, produced by gas attenuation on seismic waves, cause the low frequencies under the gas reservoirs to have stronger amplitudes compared to the amplitudes of the high frequencies. Therefore, if proper time accuracy is considered in the identification of this indicator, the gas reservoir, and consequently, its position will be identified with considerable accuracy. One of the methods of identifying low-frequency shadows is timefrequency transforms. Therefore, those time-frequency transforms that have good time and frequency resolution, can be of great help in identifying low-frequency shadows. In this research, a method called time-reassigned multisynchrosqueezing transform (TMSST) is used that acts better than common time-frequency transforms such as shorttime Fourier transform (STFT), reassignment method (RM), synchrosqueezing transform (SST) and multisynchrosqueezing transform (MSST) in terms of time and frequency resolution. Therefore, by applying this transform on a synthetic dataset and a real dataset, its performance has been demonstrated. As a seismic application, singlefrequency sections obtained from a hydrocarbon field were prepared in MATLAB environment and low-frequency shadow anomalies were detected using this time-frequency method with high resolution. In addition, in this study, the Rennie parameter, which is directly related to the sparsity, has been used to evaluate the energy concentration. The number obtained for the Rennie parameter using the method proposed in this paper is another reason for proving the remarkable performance of this method in obtaining time-frequency representation with high time and high frequency resolution at the same time.

Today there are different vibration isolators used in industries according to the weight and excitation frequency of the machines which have vibration. One of them is Air Spring which is in two types: Convoluted air spring and membrane air spring. Convoluted air springs are used to control vibrations in low frequency (usually lower than 10 Hz) and the membrane ones are used in high frequency (upper than 20 Hz). Middle frequency is between 10 and 20 Hz. Other vibration isolators are being used for this frequency range. In this paper an air spring system was made using LVDT, as the linear measurement sensor, accelerometer with PID controller and convoluted air spring. As mentioned convoluted air springs are used in low frequency but by using conclusions of this research we can use it in high frequency (about 50 Hz). Finally, an optimum vibration isolator has been made which reduce the vibration amplitude from 2.7 mm to 0.15 mm (about %87.5 reduction in vibration amplitude). Finite element analysis results have been compared with experimental results. There is a good adaption with approximately %8 error. This research has been done according to IPCO request for controlling of engine test stand vibration.

Seismic data, being non-stationary in nature, have varying frequency content across time. Time-frequency decomposition (also called spectral decomposition) of a seismic signal aims to characterize the time-dependent frequency response of subsurface rocks and reservoirs. Castagna et al. (2003) use matching-pursuit decomposition for instantaneous spectral analysis to detect low-frequency shadows beneath hydrocarbon reservoirs. A case history of using spectral decomposition and coherency to interpret incised valleys is shown by Peyton et al. (1998). Partyka et al. (1999) use windowed spectral analysis to produce discrete-frequency energy cubes for applications in reservoir characterization. Continuous wavelet transform (CWT) was introduced by Morlet et al. (1982). In CWT, time frequency atoms are chosen in such a way that their time support changes for different frequencies according to Heisenberg’s uncertainty principle (Mallat, 1999; Daubechies, 1992). This study used the Morlet wavelet, which provides an easy interpretation from scale to frequency. Time-frequency CWT (TFCWT; Sinha, 2005) analysis provides high-frequency resolution at low frequencies and high time resolution at high frequencies. This optimal time-frequency resolution property of the TFCWT makes it useful in seismic data analysis. Computing the TFCWT in the Fourier domain is a fast process. Furthermore, TFCWT is an invertible process such that the inverse Fourier transform of the time summation of the TFCWT reconstructs the original signal, provided the inverse wavelet transform exists. The purposes of this study require only the forward transform; reproducibility is not a strict requirement. Seismic data analysts sometimes observe lowfrequency shadows in association with hydrocarbon reservoirs. The shadow is probably caused by attenuation of high-frequency energy in the reservoir itself. Matching pursuit decomposition involves the cross-correlation of a wavelet dictionary against the seismic trace. The projection of the best correlating wavelet on the seismic trace is then subtracted from that trace. The wavelet dictionary is then cross-correlated against the residual, and again the best correlating wavelet projection is subtracted. The process is repeated iteratively until the energy remaining in the residual falls below some acceptable threshold. As long as the wavelet dictionary meets simple admissibility conditions, the process will converge. Most importantly, the wavelets need not be orthogonal. The output of the process is a list of wavelets with their respective arrival times and amplitudes for each seismic trace. The inverse transform is accomplished simply by summing the wavelet list and the residual, thus reconstructing the original trace. The wavelet list is readily converted to a time-frequency analysis by superposition of the wavelet frequency spectra. The CWT dilates and compresses wavelets to provide a time-scale spectrum instead of a time-frequency spectrum. Converting a scalogram into a time-frequency spectrum using the center frequency of a scale gives an erroneous attenuation in the spectrum. The TFCWT overcomes this problem and gives a more robust technique of time-frequency localization. Since TFCWT is fundamentally derived from the continuous-wavelet transform, wavelet dilation and compression effectively provides the optimal window length, depending upon the frequency content of the signal. Thus, it eliminates the subjective choice of a window length and provides an optimal time-frequency spectrum with an absence of erroneous attenuation effect for a non-stationary signal. It has highfrequency resolution at low frequencies and high time resolution at high frequencies, whereas the spectrogram has fixed time-frequency resolution throughout. Matching Pursuit Decomposition (MPD) requires no windowing of the seismic data and thus has the best combination of temporal and spectral resolution in comparison to TFCWT and the continuous wavelet transform. Most hydrocarbon reservoirs have a seismic response, but sometimes this is expressed only in certain spectral ranges, hidden within the broadband data. Gas-bearing layers have been an interesting area of research for geophysicists, especially spectral decomposition researchers, since they have a very specific spectral attribute: low-frequency gas shadows. This paper presents an investigation of the application and efficiency of Time- Frequency Continuous Wavelet Transform and Matching Pursuit method in timefrequency analysis of seismic sections to delineate and detect low-frequency gas shadows on real data from an Iranian gas reservoir. The results from the MPD are compared with those of the CWT and TFCWT applying single frequency seismic sections at frequencies of 15 Hz and 25 Hz with the expectation that low-frequency gas shadows will be observable in this range of frequencies.