A High-Reliability 12T SRAM Radiation-Hardened Cell for Aerospace Applications.

The static random-access memory (SRAM) cells used in the high radiation environment of aerospace have become highly vulnerable to single-event effects (SEE). Therefore, a 12T SRAM-hardened circuit (RHB-12T cell) for the soft error recovery is proposed using the radiation hardening design (RHBD) concept. To verify the performance of the RHB-12T, the proposed cell is simulated by the 28 nm CMOS process and compared with other hardened cells (Quatro-10T, WE-Quatro-12T, RHM-12T, RHD-12T, and RSP-14T). The simulation results show that the RHB-12T cell can recover not only from single-event upset caused by their sensitive nodes but also from single-event multi-node upset caused by their storage node pairs. The proposed cell exhibits 1.14×/1.23×/1.06× shorter read delay than Quatro-10T/WE-Quatro-12T/RSP-14T and 1.31×/1.11×/1.18×/1.37× shorter write delay than WE-Quatro-12T/RHM-12T/RHD-12T/RSP-14T. It also shows 1.35×/1.11×/1.04× higher read stability than Quatro-10T/RHM-12T/RHD-12T and 1.12×/1.04×/1.09× higher write ability than RHM-12T/RHD-12T/RSP-14T. All these improvements are achieved at the cost of a slightly larger area and power consumption.

Design and Implementation of Charge Pump Phase-Locked Loop Frequency Source Based on GaAs pHEMT Process.

This paper realized a charge pump phase locked loop (CPPLL) frequency source circuit based on 0.15 µm Win GaAs pHEMT process. In this paper, an improved fully differential edge-triggered frequency discriminator (PFD) and an improved differential structure charge pump (CP) are proposed respectively. In addition, a low noise voltage-controlled oscillator (VCO) and a static 64:1 frequency divider is realized. Finally, the phase locked loop (PLL) is realized by cascading each module. Measurement results show that the output signal frequency of the proposed CPPLL is 3.584 GHz-4.021 GHz, the phase noise at the frequency offset of 1 MHz is -117.82 dBc/Hz, and the maximum output power is 4.34 dBm. The chip area is 2701 µm × 3381 µm, and the power consumption is 181 mw.

Enzymes extracted from apple peels have activity in reducing higher alcohols in Chinese liquors.

As the unavoidable byproducts of alcoholic fermentation, higher alcohols are unhealthy compounds widespread in alcoholic drinks. To investigate the activity of apple crude enzymes toward higher alcohols in liquors, five kinds of apple peels, namely, Fuji, Gala, Golden Delicious, Red Star, and Jonagold, were chosen to prepare enzymes, and three kinds of Chinese liquors, namely, Xifeng (containing 45% ethanol), Taibai (containing 50% ethanol), and Erguotou (containing 56% ethanol), were tested. Enzymes were prepared in the forms of liquid solution, powder, and immobilized enzymes using sodium alginate (SA) and chitosan. The treatment was carried out at 37 °C for 1 h. The relative amounts of different alcohols (including ethanol, 1-propanol, isobutanol, 1-butanol, isoamylol, and 1-hexanol) were measured using gas chromatography (GC). Conditions for preparing SA-immobilized Fuji enzymes (SA-IEP) were optimized, and the obtained SA-IEP (containing 0.3 g of enzyme) was continuously used to treat Xifeng liquor eight times, 20 mL per time. Significant degradation rates (DRs) of higher alcohols were observed at different degrees, and it also showed enzyme specificity according to the apple varieties and enzyme preparations. After five repeated treatments, the DRs of the optimized Fuji SA-IEP remained 70% for 1-hexanol and >15% for other higher alcohols.

Induction of hexanol dehydrogenase in Geotrichum spp. by the addition of hexanol.

Excessive hexanol content distorts the flavor of foods and is harmful to human health. Previously, two strains of fungi were found capable of producing hexanol-degrading enzymes. The current study identified these strains as Galactomyces geotrichum according to the gene sequence of the 26 S rDNA D1/D2 region (strain S12) and genus Geotrichum according to the gene sequence of ITS region (strain S13). Parallel analysis of extracellular and intracellular enzyme activities showed that the enzymes mainly accumulated intracellularly. Native polyacrylamide gel electrophoresis with reactive dyes showed the enzymes were alcohol dehydrogenases induced by the addition of hexanol. Hexanol was catalyzed into hexanoic acid and hexanal by strain S12 and into hexanoic acid by strain S13. The optimum conditions for the induction of enzymes were determined to be 6-9 h in the presence of 0.7 g/l hexanol. The identification of two strains capable of enzymatically degrading hexanol and optimum conditions for their induction will facilitate their use in industrial applications.

Occurrence and distribution of chlorobenzenes in the Tonghui river of Beijing, China.

Eleven chlorobenzenes (CBs) in surface water and sediments of Tonghui River, a main urban drainage river of Beijing in China, were determined in October 2003, January 2004, and April 2006. CBs were widely detected and the summation operatorCB concentrations in water ranged from 89.9 to 6638.0 ng/L, with average values of 1902.8 ng/L in 2003, 2084.0 ng/L in 2004, and 1281.2 ng/L in 2006, respectively. The summation operatorCB concentrations in surficial sediments varied from 18.2 to 1827.7 ng/g dry weight (dw), with average values of 897.4 ng/g dw in 2003, 653.4 ng/g dw in 2004, and 562.6 ng/g dw in 2006, respectively. Nonparametric statistical analysis (Mann-Whitney U test) showed that there were no statistically significant changes in summation operatorCB concentrations in either surface water or sediments over the period 2003-2006. The distribution pattern of CBs in the Tonghui River indicates that further effort is warranted in reducing local sources of contaminants. Additionally, the summation operatorCB levels in sediment samples were found to be dependent on total organic carbon contents.