High-spin states in neutron-rich 102Mo nucleus

High-spin states in neutron-rich 102Mo nucleus have been studied by measuring the prompt γ-rays in the spontaneous fission of 252Cf. The previous level scheme has been updated and some new levels and transitions are identified. The one-phonon γ-band is expanded and a band head level of the two-phonon γ-band is proposed. The systematic characteristics of yrast bands, one-phonon γ-bands, two-phonon γ-bands and quasi-particle bands in 102Mo, 104Mo and 106Mo are discussed.     

立式螺旋管汽液两相流沸腾传热恶化实验研究

本文实验研究了低质量流速(500～800 kg·m~(-2)·s~(-1))下的立式螺旋管临界热负荷,对沸腾传热恶化壁温特性和螺旋管临界热负荷影响因素进行分析.并同前人工作汇总,以流量,压力和临界干度为参数,建立了基于局部条件假设的立式螺旋管临界热负荷查询表(Look-Up-Table),共272个点.压力范围6.5～21 MPa,质量流速范围500～1800 kg·m~(-2)·s~(-1).     

基于超声红外技术对金属管内壁缺陷的检测

为提高管道的运送效率,及时检测排除管道内壁的缺陷非常重要。提出利用超声红外无损检测方法对管道内部进行检测。超声主动热激励试件,高频红外热像仪记录试件表面温度变化,结合了超声摩擦生热和红外热成像的优点。对壁厚约为3.3mm检测难度较大的金属管内壁缺陷进行了检测。通过对采集数据和热图的处理分析,准确快速地确定缺陷所在的位置。实物对比分析表明：超声热激励红外无损检测技术可以对金属管道内壁缺陷进行准确检测定位。     

应用ICP-AES法研究云南普洱茶稀土含量

应用电感耦合等离子体发射光谱法(ICP-AES)对云南省普洱茶主产地采集的150份普洱茶样品的稀土含量进行检测研究.检测样品中稀土的含量在0.26～4.07 mg·kg-1范围.依据国家标准GB 2762-2005<食品中污染物限量>中稀土限量标准2 mg·kg-1考核,43%的普洱茶样品被检出稀土含量超标.云南普洱熟茶和生茶不同的生产工艺会造成普洱茶稀土含量的差异,并影响产品质量.云南普洱茶不同主产地区之间的稀土含量存在差异,个别地区的普洱茶稀土质量安全控制情况不容乐观.     

脉冲X射线剂量率测量不确定度分析

“强光一号”短脉冲高能X射线剂量率测量,主要包括脉冲射线总剂量与脉冲射线时间宽度的测量,前者采用热释光剂量计测量,后者采用PIN半导体探测器记录。根据不确定度传递数学模型,分析了影响X射线剂量和脉冲宽度测量结果的因素。针对“强光一号”短脉冲高能X射线测量,定量地给出了各种因素引入的测量不确定度,总剂量测量是影响剂量率测量准确性的决定性因素,其相对标准不确定度为25.1％,脉冲宽度测量不确定度为3.7％,剂量率测量扩展不确定度为50.8%,置信概率95%。     

原位微区X射线荧光分析在矿物学研究中的应用

从新疆采集了13件岩矿石样品,用于研究蚀变过程中矿物的元素含量变化特征。成都理工大学研制的IED-6000型原位微区X射线荧光分析仪被应用于获得蚀变过程中矿物的化学和物理数据。这种无损的微区X射线荧光分析仪主要是以低功耗X光管和电致冷Si-PIN半导体探测器为基础,采用毛细管X射线透镜实现微区测量的功能,并且能够集成到任何显微镜上进行测量,焦斑长轴直径约110 μm。通过微区X射线荧光测量,将黝铜矿更正为黄铁矿,提高了矿物鉴定的效率及准确性;在蚀变剖面研究中,矿化岩石样品的长石颗粒都富含Cu和Zn元素,可以作为找矿直接指示元素。Cr,Mn和Co等元素含量与矿化程度呈负相关。     

啁啾相移光纤光栅分布式应变与应变点精确定位传感研究

利用啁啾相移光纤光栅狭缝的中心波长对应变点和应变量的波长敏感性,实现应变与应变点精确定位的传感.当啁啾光纤光栅上的某一位置产生微应变时,该应变点会产生相移,其频谱则会出现一个与之对应的狭缝,且狭缝的深度和中心波长与应变的大小和位置相关.当串接不同中心波长的啁啾光纤光栅后,即可实现一定范围内的分布式应变与应变点精确定位检测.本文通过V-I传输矩阵法建立了狭缝深度和中心波长关于应变量和应变位置的理论模型,分析结果表明理论上可以实现微米量级的精确定位.搭建了级联啁啾相移光纤光栅的分布式应变传感装置,实验获得的最大应变灵敏度为0.19 pm/με.该精确定位传感装置在先进制造、精密加工、航空航天、铁路系统等高新技术领域具有重要的应用前景.     

GESFIDE-PROPELLER Approach for Simultaneous R2 and R2* Measurements in the Abdomen

Purpose

To investigate the feasibility of combining GESFIDE with PROPELLER sampling approaches for simultaneous abdominal R2 and R2* mapping.

Materials and Methods

R2 and R2* measurements were performed in 9 healthy volunteers and phantoms using the GESFIDE-PROPELLER and the conventional Cartesian-sampling GESFIDE approaches.

Results

Images acquired with the GESFIDE-PROPELLER sequence effectively mitigated the respiratory motion artifacts, which were clearly evident in the images acquired using the conventional GESFIDE approach. There was no significant difference between GESFIDE-PROPELLER and reference MGRE R2* measurements (p = 0.162) whereas the Cartesian-sampling based GESFIDE methods significantly overestimated R2* values compared to MGRE measurements (p < 0.001).

Conclusion

The GESFIDE-PROPELLER sequence provided high quality images and accurate abdominal R2 and R2* maps while avoiding the motion artifacts common to the conventional Cartesian-sampling GESFIDE approaches.     

Chemical composition and magnetism of Ag doped LaMnO3

By using a sol-gel clue, a set of polycrystalline perovskite samples La$_{1 - x}$Ag$_{x}$MnO$_{3}$ with a nominal doping level $x$ ranging from 0.05 to 0.45 has been synthesized. The chemical composition and the magnetism of the samples were investigated. A little Ag was found seeping from the samples in the sintering process when the doping level exceeded 0.05 and the sintering temperature was higher than 700\du\, resulting in the samples being in multiphase. The magnetic transition points of the samples have been found to decrease with increasing sintering temperature. A concentration-dependent $T_{\rm c}$ similar to that of bivalent metal ion doped perovskite, has been obtained. We believe that the Ag seeping in the sintering process is responsible for those magnetic characteristics.