NAND flash service lifetime estimate with recovery effect and retention time relaxation

A service life model of NAND flash and threshold voltage shift process is proposed to calculate the service life and endurance.The relationships among achievable program/erase(P/E) cycles,recovery time,bad block rate and storage time are analyzed.The achievable endurance and service life of a NAND flash are evaluated based on a flash cell degradation and recovery model by varying recovery time,badblock rate,and storage time.It is proposed to improve the service lifetime of solid state disk by both relaxing the bad block rate limitation and retention time while extending the recovery time.The results indicate that endurance can be improved by 17 times if the storage time guarantee is reduced from 10 a to 1 a with 105 s recovery time inserted between cycles.

A sink moving scheme based on local residual energy of nodes in wireless sensor networks

In the application of periodic data-gathering in sensor networks,sensor nodes located near the sink have to forward the data received from all other nodes to the sink,which depletes their energy very quickly.A moving scheme for the sink based on local residual energy was proposed.In the scheme,the sink periodically moves to a new location with the highest stay-value defined by the average residual energy and the number of neighbors.The scheme can balance energy consumption and prevent nodes around sink from draining their energy very quickly in the networks.The simulation results show that the scheme can prolong the network lifetime by 26%-65%compared with the earlier schemes where the sink is static or moves randomly.

Effect of Vacuum Cooling on Shelf Life of Organic Chayote Shoot （Sechium edule Sm.）

The effect of vacuum cooling on shelf life of organic chayote was investigated. Vacuum cooling processes of organic chayote shoot packed in perforated polyethylene package using different vacuum pressure reserving operation modes were experimented. The holding final pressures for vacuum-cooled organic cilantro packed in holed polyethylene bags were set at two different levels, namely at 10 and 11 millibar. The pressures were experimented with 3 levels of reserving time of 3, 4 and 5 minutes. The weight loss percentage of chayote shoot during precooling to the temperature of 8 ~ 1 ~C using reserving pressure of 10 milibars for 3, 4, and 5 minutes were 0.5, 0.7, and 0.9, respectively. For the weight loss percentage during precooling using reserving pressure of 11 milibars for 3, 4, and 5 minutes were 0.4, 0.5, and 0.5, respectively. The optimum parameter for vacuum cooling process of organic chayote shoot at the initial temperature of 19-23 ℃to 8 ±1 ℃was the reserving pressure of 11 mbar with reserving time of 5 minutes. The precooled organic chayote shoot was then stored at 8 ℃ for quality analysis. The results showed that vacuum cooling had no effect on the change of color, chlorophyll a, b and total chlorophyll. However, precooled organic chayote shoots showed better appearance than non-precooled vegetables. Vacuum cooling can reduce weight loss percentage. The amount of total soluble solids in organic chayote shoots increased with storage time. Precooled organic chayote shoot had longer shelf life of 8 days compared to normal storage life of 5 days.

Increased life-span of Drosophila melanogaster by Flavonoids from Scutellariabaicalensis Georgi induced by hydrogen peroxide

Objective： To explore the effects and mechanisms of flavonoids from Scutellaria baicalensis Georgi in hydrogenperoxide （H2O2） induced Drosophila melanogaster model. Method： H2O2 induced Drosophila melanogaster agingmodel was used to study the effects of flavonoids from Scutellaria baicalensis Georgi. Secondly, the effects ofbaicalein and wogonin on mRNA expressions were examined. Results： Our results found that baicalein andwogonin could extend the life-spans of H2O2 induced Drosophila melanogaster aging model via increased mRNAexpressions of superoxide dismutase catalase and rosy. Conclusion： Baicalein and wogonin could extend life-spansof H2O2 induced Drosophila melanogaster aging model through increasing mRNA expressions of superoxidedismutase, catalase and rosy.

Effects of Clouds and Aerosols on Surface Radiation Budget Inferred from DOE AMF at Shouxian,China

Based on data collected during the first U.S. Department of Energy （DOE） Atmospheric Radiation Measurement （ARM） field campaigns at Shouxian, east- ern China in 2008, the effects of clouds and aerosols on the surface radiation budget during the period Octo- ber-December 2008 were studied. The results revealed that the largest longwave （LW）, shortwave （SW）, and net Aerosol Radiative Effects （AREs） are 12.7, -37.6, and -24.9 W rn-2, indicating that aerosols have LW warming impact, a strong SW cooling effect, and a net cooling ef- fect on the surface radiation budget at Shouxian during the study period 15 October-15 December 2008. The SW cloud radiative forcing （CRF） is -135.1 W m-2, much cooler than ARE （about 3.6 times）, however, the LW CRF is 43.6 W m 2, much warmer than ARE, and resulting in a net CRF of-91.5 W m-2, about 3.7 times of net ARE. These results suggest that the clouds have much stronger LW warming effect and SW cooling effect on the surface radiation budget than AREs. The net surface radiation budget is dominated by SW cooling effect for both ARE and CRE. Furthermore, the precipitatable clouds （PCs） have the largest SW cooling effect and LW warming ef- fect, while optically thin high clouds have the smallest cooling effect and LW warming on the surface radiation budget. Comparing the two selected caseds, CloudSat cloud radar reflectivity agrees very well with the AMF （ARM Mobile Facility） WACR （W-band ARM Cloud Radar） measurements, particularly for cirrus cloud case. These result will provide a ground truth to validate the model simulations in the future.

北京地区出土金银器概述

万历帝后墓出土大批首饰,其中以簪为数最多,制作也最精美。簪的制作,包括打制、雕刻、累丝、琢玉、镶嵌、焊接等多道工序。簪顶多为立体造型,设计新颖,玲珑剔透,精巧华丽。花样款识多样,佛教内容有佛像、菩萨、宝塔、佛字等;人物装饰有仙人寿星及童子;动物之属有龙凤、仙鹤、鸳鸯、龟、鹿及花草虫蝶等;植物之属有花果、寿果和灵芝等,还有'万寿'、'喜庆万年'等吉语。例如塔形金簪。

Green synthesis of fluorescent carbon quantum dots and carbon spheres from pericarp

An economical idea was developed to synthesize fluorescent carbon quantum dots （CQDs） directly fl-om the refluxing extraction of orange pericarp via a hydrothermal technique. Hydrothermal temperatures and times were adjusted to control the particle sizes and the quantum yields of the obtained CQDs. The as-prepared carbon quantum dots showed narrow particle size distribution, good water solubility, and acceptable fluorescence lifetimes. Due to their high stability, these obtained carbon quantum dots have great application potential in nano-biotechnology. Furthermore, carbon spheres with uniform morphology and size can be easily obtained as the reaction byproducts of this green synthesis process.