Stepped-up development of accelerator mass spectrometry method for the detection of ^(60)Fe with the HI-13 tandem accelerator

The Moon provides a unique environment for investigating nearby astrophysical events such as supernovae.Lunar samples retain valuable information from these events,via detectable long-lived“fingerprint”radionuclides such as^(60)Fe.In this work,we stepped up the development of an accelerator mass spectrometry(AMS)method for detecting^(60)Fe using the HI-13tandem accelerator at the China Institute of Atomic Energy(CIAE).Since interferences could not be sufficiently removed solely with the existing magnetic systems of the tandem accelerator and the following Q3D magnetic spectrograph,a Wien filter with a maximum voltage of±60 kV and a maximum magnetic field of 0.3 T was installed after the accelerator magnetic systems to lower the detection background for the low abundance nuclide^(60)Fe.A 1μm thick Si_(3)N_(4) foil was installed in front of the Q3D as an energy degrader.For particle detection,a multi-anode gas ionization chamber was mounted at the center of the focal plane of the spectrograph.Finally,an^(60)Fe sample with an abundance of 1.125×10^(-10)was used to test the new AMS system.These results indicate that^(60)Fe can be clearly distinguished from the isobar^(60)Ni.The sensitivity was assessed to be better than 4.3×10^(-14)based on blank sample measurements lasting 5.8 h,and the sensitivity could,in principle,be expected to be approximately 2.5×10^(-15)when the data were accumulated for 100 h,which is feasible for future lunar sample measurements because the main contaminants were sufficiently separated.

First proof-of-principle experiment with the post-accelerated isotope separator on-line beam at BRIF:measurement of the angular distribution of ^(23)Na+^(40)Ca elastic scattering

The reaction dynamics of exotic nuclei near the drip line is one of the main research topics of current interest.Elastic scattering is a useful probe for investigating the size and surface diffuseness of exotic nuclei.The development of rare isotope accelerators offers opportunities for such studies.To date,many relevant measurements have been performed at accelerators using the projectile fragmentation technique,while the measurements at accelerators using isotope separator on-line(ISOL)systems are still quite scarce.In this work,we present the first proof-of-principle experiment with a post-accelerated ISOL beam at the Beijing Radioactive Ion Beam Facility(BRIF)by measuring the angular distribution of elastic scattering for the stable nucleus^(23)Na from the doubly magic nucleus^(40)Ca at energies above the Coulomb barrier.The angular distribution measured by a silicon strip detector array in a scattering chamber using the ISOL beam at BRIF is in good agreement with that measured by the high-precision Q3 D magnetic spectrograph using the nonISOL beam at nearly the same energy.This work provides useful background for making BRIF a powerful tool for the investigation of the reaction dynamics of exotic nuclei.

Experimental study of temperature dependence of single-event upset in SRAMs

We report on the temperature dependence of single-event upsets in the 215–353 K range in a 4M commercial SRAM manufactured in a 0.15-lm CMOS process,utilizing thin film transistors. The experimental results show that temperature influences the SEU cross section on the rising portion of the cross-sectional curve(such as the chlorine ion incident). SEU cross section increases 257 %when the temperature increases from 215 to 353 K. One of the possible reasons for this is that it is due to the variation in upset voltage induced by changing temperature.

Application of ML to System Identification for Underwater Vehicle

In this paper, maximum-likelihood (ML) and its relaxation algorithm, which are used to identify the mathematicsmodel of an underwater vehicle(UV), arc discussed. With the trial data of zigzag tests, the hydrodynamic derivatives of theUV were estimated, and the relaxation algorithm is confirmed to have better astringency from the contrast between the twomethods.Then a simulation environment based on these parameters is established to verify the validity and effect of these meth-ods. The result shows the model is credible and the methods are very useful for the research of maneuverability and adaptivecontrol of underwater vehicles.

肉鸡日粮中添加发酵棉粕对其组织脂类代谢及肝脏代谢谱的影响（英文）

目的:旨在研究发酵棉粕对肉鸡脂类代谢的影响。创新点:将荧光定量聚合酶链反应PCR和代谢组学方法相结合,就采食发酵饲料(发酵棉粕)肉鸡的组织脂类代谢相关基因及肝脏代谢谱进行分析,发现发酵棉粕具有调控肉鸡脂类代谢的作用。该研究为研究日粮中复杂营养素对动物机体代谢的调控提供了新思路。方法:将180只21日龄肉鸡随机分为三组,每组6个重复,每个重复10只鸡。对照组饲喂未发酵棉粕底物,试验组分别饲喂热带假丝酵母发酵棉粕和热带假丝酵母与酿酒酵母复合发酵棉粕。饲喂21天后,采集肉鸡腹部脂肪和肝脏进行组织基因表达和肝脏代谢组学分析。结论:发酵棉粕可通过下调肝脏FAS、ACC和腹脂LPL等基因的表达,改变肝脏多种内源性代谢的代谢途径,进而降低肉鸡腹部脂肪沉积和肝脏甘油三酯含量。