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161.
Bahare Pasandide Faramarz Khodaiyan Zeinab Mousavi Seyed Saeid Hosseini 《Food science and biotechnology》2018,27(4):997-1005
In this study, the effect of acidic extraction conditions (time of 30–90 min, temperature of 75–95 °C and pH of 1.5–3) on the yield and degree of esterification (DE) of citron peel pectin was investigated applying Box–Behnken design. The highest production yield of pectin (28.31?±?0.11%) was achieved at extraction time of 90 min, temperature of 95 °C and pH of 1.5, as optimal extraction conditions, which was close to the predicted value (29.87%). Under optimum extraction conditions, the DE and the emulsifying activity were 51.33 and 46.2%, respectively. In addition, the emulsions were 93.9 and 93.5 stable at 4 °C, 93.7 and 93.1 at 23 °C after 1 and 30 days, respectively. The determination of flow behavior showed that the pectin solutions had a Newtonian behavior at low concentrations (<?1.0% w/v), while this behavior was changed to pseudoplastic with increasing concentration. 相似文献
162.
Hossein Delshab Parvin Farshchi Faramarz Moattar 《The International journal of environmental studies》2017,74(6):1031-1043
The current study examines biometric parameters and concentration of some heavy metals in soft tissues of Saccostrea cucullata in the Asaluyeh coast, Persian Gulf, Iran. The metals concentration in the soft tissue of the Saccostrea cucullata ranged as: Zn: 765–3411 mg kg?1, Cu: 120.3–580.6 mg kg?1, Cd: 0.13–3.5 mg kg?1, As: 0.39–3.3 mg kg?1, Pb: 0.05–1.64 mg kg?1, Ni: 0.02–0.44 mg kg?1, V: 0.06–0.32 mg kg?1, Cr: 0.02–0.16 mg kg?1 and Hg: 0.002–0.068 mg kg?1. The results showed that the concentration of total heavy metals in oysters of the control station (CA) is usually lower. The results also indicated lack of correlation between oyster biometric parameters and bioaccumulated heavy metals, except between Cu and longitudinal diameter (R = 0.77). The concentration of heavy metals is higher than limits recommended by the World Health Organization, except for Cd and Pb. 相似文献
163.
We investigate the application of irregular repeat-accumulate (IRA) codes in volume holographic memory (VHM) systems. We introduce methodologies to design efficient IRA codes. We show that a judiciously designed IRA code for a typical VHM can be as good as the optimized irregular low-density-parity-check codes while having the additional advantage of lower encoding complexity. Moreover, we present a method to reduce the error-floor effect of the IRA codes in the VHM systems. This method explores the structure of the noise pattern in holographic memories. Finally, we explain why IRA codes are good candidates for the VHM systems. 相似文献
164.
Results on Punctured Low-Density Parity-Check Codes and Improved Iterative Decoding Techniques 总被引:1,自引:0,他引:1
Hossein Pishro-Nik Faramarz Fekri 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2007,53(2):599-614
This paper first introduces an improved decoding algorithm for low-density parity-check (LDPC) codes over binary-input-output-symmetric memoryless channels. Then some fundamental properties of punctured LDPC codes are presented. It is proved that for any ensemble of LDPC codes, there exists a puncturing threshold. It is then proved that for any rates R1 and R2 satisfying 012<1, there exists an ensemble of LDPC codes with the following property. The ensemble can be punctured from rate R1 to R2 resulting in asymptotically good codes for all rates R1lesRlesR2. Specifically, this implies that rates arbitrarily close to one are achievable via puncturing. Bounds on the performance of punctured LDPC codes are also presented. It is also shown that punctured LDPC codes are as good as ordinary LDPC codes. For BEC and arbitrary positive numbers R12<1, the existence of the sequences of punctured LDPC codes that are capacity-achieving for all rates R1 lesRlesR2 is shown. Based on the above observations, a method is proposed to design good punctured LDPC codes over a broad range of rates. Finally, it is shown that the results of this paper may be used for the proof of the existence of the capacity-achieving LDPC codes over binary-input-output-symmetric memoryless channels 相似文献
165.
166.
Hendessi Faramarz Sheikh Asrar U.H. Hafez Roshady M. 《Wireless Personal Communications》2000,12(3):239-253
In this paper, the impact of co-channel and adjacent channel interference in mobile cellular radio systems on the cellular system capacity are studied. Simple empirical expressions for average signal to co-channel, signal to adjacent channel and signal to total interference ratios are obtained. The simple empirical results developed in this paper are easier to use in a cellular system design. The maximum number of bits/sec that can be transmitted over a cell area for a given bit error rate and total bandwidth, is proposed as a new definition of capacity of digital cellular systems. The capacity of a cellular system is shown to depend on the excess bandwidth and the number of active users. 相似文献