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Cai Kui Schouhamer Immink Kees A. Lee Yuan Xing Qin Zhiliang Chong Tow Chong 《Selected Areas in Communications, IEEE Journal on》2010,28(2):208-217
This paper proposes efficient distance-enhancing constrained codes with parity-check (PC) constraints for data storage channels. We first propose simple and efficient finitestate encoding methods to design various distance-enhancing constrained codes, including a repeated minimum transition runlength (RMTR) code for optical recording channels, as well as a maximum transition run (MTR) code for magnetic recording channels. We further propose a general and systematic code design methodology, which can efficiently combine constrained codes with PC codes. The constrained codes can be any distanceenhancing constrained codes. The PC codes can be any linear binary PC codes. The rates of the designed codes are only a few tenths of a percent below the theoretical maximum. The proposed method enables soft information to be available to the PC decoder and soft decoding of PC codes. Examples of several newly designed distance-enhancing constrained PC codes are illustrated. Simulation results with blu-ray disc (BD) systems show that the proposed new RMTR code and RMTR constrained 4-bit PC code perform 0.2 dB and 0.85 dB better than the standard 17PP code, respectively, at error correction code (ECC) failure rate (EFR) of 10-12 and high recording density. 相似文献
885.
Zhi-gang Yu Zhi Qin Hong-rui Ji Xia Du Yan-hui Chen Ping Pan Heng Wang Yu-yong Liu 《Chromatographia》2010,72(11-12):1073-1081
A method for the simultaneous determination of 11 triazine herbicides residues in river water has been developed. It involves solid-phase extraction (SPE) pretreatment step and rapid resolution liquid chromatography-tandem mass spectrometry (RRLC-MS-MS). In the SPE pretreatment step, the adsorptive performance of MWCNTs material as SPE adsorbent and the elution capability of five kinds of solvents were investigated; in the LC separation step, a rapid resolution high throughput LC column, was used and the gradient elution mode adopted. The linear correlation coefficients (r 2) of the method for 11 target analytes varied between 0.9930 and 0.9980, the mean recoveries were in the range of 73.0 and 98.0% with relative standard deviations (RSD) 2.6 ~ 4.2%, the method detection limits (MDL) were all below 0.1 ng L?1. An expanded uncertainty of not more than 20% was estimated for each analyte at the spiked concentration of 4.0 μg L?1. The proposed method was applied to the determination of the residue concentrations of 11 pollutants in Songhuajiang River water. 相似文献
886.
The geometries,electronic structure,IR spectrum and other properties of hydrogen interaction between 5-fluorouracil and glycine were studied at the B3LYP/6-31+G* level.Single point energy calculations were executed at the B3LYP/6-311++G** and B3LYP/aug-cc-pvdz levels,and natural bond orbital (NBO) analysis was carried out at the B3LYP/6-31+G* level.Finally,the hydrogen bonds were discussed via AIM electronic density topology analysis. 相似文献
887.
建立了高效液相色谱-质谱(LC-MS/MS)检测水产品中喹乙醇代谢物3甲-基-喹恶啉-2羧-酸(MQCA)的残留分析方法。样品先用Protease蛋白酶酶解,然后用乙酸乙酯萃取目标物,氮气吹干后用流动相溶解残渣,以甲醇、乙腈和0.1%甲酸溶液作为流动相,液相色谱串联电喷雾质谱在正离子模式下测定。MQCA在1~100μg/kg范围内线性关系良好(r0.999)。在2、4、8μg/kg3个添加水平上,回收率在82.5%~87.5%,相对标准偏差为4.5%~5.1%(n=6),定量限为1μg/kg。方法已用于水产品中喹乙醇代谢物的残留分析。 相似文献
888.
By controlling the reflux time and the quantity of the shell materials, different sizes of thioglycollic acid (TGA) modified
CdTe/CdSe core/shell quantum dots were synthesized in aqueous solution. This type of QDs was used for sensitive and selective
determination of ascorbic acid in commercial tablets. Under optimal conditions, a good linearity was observed between the
relative fluorescence (FL) intensity and the concentration of ascorbic acid in the range of 4.0 to 64.0 μg/mL with a correlation
coefficient of 0.9968. The limit of detection was 2.4 μg/mL. This method was applied to the determination of the ascorbic
acid in Vitamin C tablets and Vitamin C Yinqiao pills, and satisfactory results were obtained. 相似文献
889.
We demonstrate widely tunable soliton and dispersive wave source generation in a highly nonlinear tellurite microstructured
fiber pumped by a 1550 nm femtosecond fiber laser. The spectral range covered by the soliton and dispersive wave source is
as wide as 1100 nm from 1150 to 2250 nm. It is shown that the spectral linewidth of the soliton and dispersive wave can be
controlled by changing the length of the tellurite microstructured fiber easily owing to the dispersion-induced pulse broadening
effects. This light source using tellurite microstructured fiber could open wide applications. 相似文献
890.
Enhanced soliton trapping of dispersive waves in a tapered tellurite microstructured fiber pumped by a 1556 nm femtosecond
fiber laser is demonstrated. The short wavelength edge of supercontinuum light is extended from 960 to 600 nm after tapering
the tellurite microstructured fiber, which is caused by the enhanced soliton trapping of dispersive waves owing to the changing
group velocities in tapered fibers. Wide-band supercontinuum light source spanning from 600 to >2400 nm is generated in tapered
tellurite micro-structured fibers. Our experimental and simulated results show that short length (several centimeters) zero-dispersion-wave
length decreasing highly nonlinear fiber has a potential for generating wideband supercontinuum light source expanding from
visible to mid-infrared region. 相似文献