手持式消光光度计的研制及用于掺杂牛奶的现场快速检测     

花榕  张兴磊  周跃明  胡燕  张燮  陈焕文 《岩矿测试》2008,27(3):169-173

自行设计新型消光池,研制了一种廉价的手持式消光光度计,并在此基础上建立了掺杂牛奶的现场检测方法。实验结果表明,所建立的方法无需对牛奶进行复杂处理,可对常见掺杂(如搀水、米汤、奶粉、豆浆、尿素等)牛奶和含重金属离子汞的牛奶,进行现场检测。由于采用新型消光池,有效地减小了蛋白质粒子因重力沉降所带来的误差,能够成功区分同密度劣质牛奶。该方法灵敏度高,对掺水牛奶的检出限低于2%,对重金属(如汞)的检出限为0.005μg/g。单个样品测定时间不到2 min,适合于牛奶品质的现场快速检测。  相似文献   

基于移动地图学的空间信息系统     

王悦  吴云东  赵春川 《测绘工程》2008,17(1):44-47

在地理信息广泛应用的今天,基于移动地图学的空间信息系统对于广大用户越来越重要。以空间信息移动服务为平台的智能系统必然成为地图学的一个重要的发展方向。通过分析移动地图学的发展趋势,结合地图学与其他学科交叉的现状,以地图学的观点分析空间信息移动服务系统发展的关键因素。并简要介绍现有的软硬件设备存在的不足。概括移动服务的应用,对其前景进行展望。  相似文献   

Magnetic reconnection in solar flares     

T. G. Forbes 《地球物理与天体物理流体动力学》2013,107(1-4):15-36

Abstract

The magnetic energy stored in the corona is the only plausible source for the energy released during large solar flares. During the last 20 years most theoretical work has concentrated on models which store magnetic energy in the corona in the form of electrical currents, and a major goal of present day research is to understand how these currents are created, and then later dissipated during a flare. Another important goal is to find a flare model which can eject magnetic flux into interplanetary space. Although many flares do not eject magnetic flux, those which do are of special importance for solar-terrestrial relations since the ejected flux can have dramatic effects if it hits the Earth's magnetosphere. Three flare models which have been extensively investigated are the emerging-flux model, the sheared-arcade model, and the magnetic-flux-rope model. All of these models can store and release magnetic energy efficiently provided that rapid magnetic reconnection occurs. However, only the magnetic-flux-rope model appears to provide a plausible mechanism for ejecting magnetic flux into interplanetary space.  相似文献   

铀的紫外-可见分光光度分析专用试剂包的开发研究     

黄龙珠  杨水平  张兴磊  陈焕文  肖赛金 《铀矿地质》2012,(5):311-316,320

利用新开发的铀试剂包和自行研制的手持式光度计,建立了环境水样中痕量铀的现场分析新方法。实验中分别考察了缓冲试剂、显色剂、掩蔽剂的选择及用量、显色时间稳定性、波长等主要因素对铀分析测定的影响。结果表明,与经典紫外-可见分光光度法相比,此方法具有操作简便、省时、满足现场测定要求等优点。  相似文献   

甘肃金塔地区大气对太阳射电辐射吸收的测量研究     

刘炎  李东  宋其武  孟璇  许富英  吴洪敖  宁宗军 《天文学报》2011,52(5):377-384

2008年8月1日,在我国西北的新疆、内蒙、甘肃等地区可以观测到一次日全食的天象,紫金山天文台太阳射电团组在甘肃省金塔用两架太阳射电望远镜对这次日全食进行了观测,并成功地取得了观测资料.为了科学分析观测资料,在日全食的前两天,实测了当地的大气吸收.着重分析这些观测数据,结合太阳射电方法,测得在λ=2.4 cm和λ=8....  相似文献   

日晕测量与日晕光度计外缘杂散光抑制试验     

刘念平  刘煜  申远灯  张雪飞  曹文达  Arnaud Jean 《天文学报》2011,52(2)

为配合大型太阳设备西部选址工作,研制了一架现代日晕光度计(Sky Brightness Monitor,SBM).前期实验对日晕光度计性能进行了测试,同时积累了云南部分址点的日晕数据.资料分析结果显示,轿子雪山正午前后的日晕水平最低可至日面中心强度百万分之几的量级(蓝波段).这表明该日晕光度计内部杂散光水平已达到了国际同类产品的标准.日晕光度计的内部杂散光源主要来自两部分:镜筒前端中性滤光片(ND4)固定套圈的边缘衍射(视场靠内区域)和镜筒内置光阑的边缘衍射(视场靠外区域).针对后者进行的变换光阑孔径大小试验结果证实,适当缩小光阑孔径可有效减小数据中视场靠外区域的衍射光干扰.  相似文献   

Two Sympathetic Homologous CMEs on 2002 May 22     

Jian-Xia Cheng  Cheng Fang  Peng-Fei Chen  Ming-De Ding Department of Astronomy  Nanjing University  Nanjing   《中国天文和天体物理学报》2005,5(3):265-272

Sympathetic coronal mass ejections (CMEs) usually occur in different active regions connected by interconnecting magnetic loops, while homologous CMEs occur within the same active region with an almost the same background magnetic field, and so are similar in shapes. Two sympathetic CMEs erupted within 3 hours on 2002 May 22, originating from the same active region, AR 9948. Their multi-wavelength data were collected and analyzed. It is suggested that emerging flux triggered the occurrence of the first CME and the corresponding flare, the reconnection inflow of which in turn triggered the eruption of the second CME. Based on the fact that the two sympathetic CMEs have many similarities, in their shapes, their low-lying dimming areas, etc., we tentatively propose, for the first time, the phenomenon of sympathetic homologous CMEs.  相似文献   

太阳分米波射电快速精细结构的观测分析     

段长春  汪敏  许春  谢瑞祥 《天文研究与技术》2002,(4):19-28

通过分析云南天文台(YNO)0.7～1.5GHz太阳射电频谱仪2000年9月至2001年9月取得的158个射电爆发,发现其中约有65%存在4类不同类型的快速精细结构(FFS):毫秒尖峰辐射、Ⅲ型爆发、准周期脉动、慢漂移结构。给出了其中6个典型精细结构的介绍和相关的初步解释。  相似文献   

Excitation of solar-like oscillations: From PMS to MS stellar models     

R. Samadi  M. -J. Goupil  E. Alecian  F. Baudin  D. Georgobiani  R. Trampedach  R. Stein  å. Nordlund 《Journal of Astrophysics and Astronomy》2005,26(2-3):171-184

The amplitude of solar-like oscillations results from a balance between excitation and damping. As in the sun, the excitation is attributed to turbulent motions that stochastically excite thep modes in the uppermost part of the convective zone. We present here a model for the excitation mechanism. Comparisons between modeled amplitudes and helio and stellar seismic constraints are presented and the discrepancies discussed. Finally the possibility and the interest of detecting such stochastically excited modes in pre-main sequence stars are also discussed.  相似文献   

太阳活动周期的小波分析   总被引：5，自引：0，他引：5  

占腊生  何娟美  叶艺林  赵海娟 《天文学报》2006,47(2):166-174

运用小波技术对太阳射电流量2800 MHz,太阳黑子数和太阳黑子面积数周期进行分析．其结果表明: (1)这3个系列的数据显示最显著的周期是10．69年,其他周期并不明显．(2)小波功率谱给出了全部时间-周期范围的功率谱变化,它显示了在某个周期处于某个时段的局部功率的变化,小波功率谱分析表明,小于1年的周期仅仅在太阳活动最大期附近比较明显．(3)太阳射电2800 MHz,太阳黑子数和太阳黑子面积数的几个周期(10．69年,5．11年, 155．5天)的小波功率谱比较相似,出现峰值的时间相同;曲线的起伏相似,周期越小,曲线起伏的频率越大．  相似文献