Pseudo-dipole signal removal from WMAP data

We have discovered in our previous work that different observational systematics, e.g. errors from antenna pointing directions or an asynchronism between the attitude and science data may generate a pseudo-dipole signal in the full-sky maps of the cosmic microwave background (CMB) anisotropy that have been published by the Wilkinson Microwave Anisotropy Probe (WMAP) team. We have found that the antenna sidelobe response to the Doppler signal produces a similar effect. In this work, independent from the sources, we have uniformly modeled the pseudo-dipole signal and have removed it from the published WMAP7 CMB maps by model fitting. The result demonstrates that the released WMAP CMB quadrupole is almost completely artificial.     

Inconsistency between WMAP data and released map

A remarkable inconsistency between the calibrated differential time-ordered data (TOD) of the Wilkinson Microwave Anisotropy Probe (WMAP) mission,which is the input for map-making,and the cosmic microwave background (CMB) temperature maps published by the WMAP team is revealed,indicating that there must exist a serious problem in the map making routine of the WMAP team.This inconsistency is easy to be confirmed without the use of WMAP map-making software.In view of the importance of this issue for cosmology...     

微波背景观测与早期宇宙研究

微波背景观测与早期宇宙研究尚处于学科发展的初期阶段,对探测方法、背景(前景)处理、系统误差及结果可靠性的认识都有待深入.发现微波探测卫星WMAP公布的宇宙微波背景辐射温度图存在严重的系统误差后,几年来我们重新进行了数据分析,修正了时钟同步、天线旁瓣误差导致的伪偶极信号,得到的背景辐射温度图和功率谱与WMAP发布的结果有重大差异,引起了广泛关注,讨论和争论.本文概述有关工作及论争的过程与现状,及其对于早期宇宙研究的影响.     

分子（HX，X=F，CI，Br）的电学性质的全相对论研究

基于全对称群的Dirac方程,研究分子（HX,X=F,C1,Br）的电学性质,即偶极矩,四极矩,电场梯度和极化率及其随频率的变化．对这种轻元素分子的相对论和非相对论的能量差,即相对论效应随原子质量的增加仍然很快．偶极矩的电荷平衡分布,HF的差别最大,而对四极矩的电荷平衡分布,则HBr的差别最大．电偶极矩的一级近似是主要部分,电四极矩为二级近似则为次要部分．本文首次将力常数与电场梯度联系起来,因为从本质上讲,力常数是直接原因于电场梯度,而间接与光谱常数有联系,所以可由电场梯度可以计算分子的二阶力常数和谐振频率,对分子HF,HC1,HBr,其计算值与光谱值相合．计算所用的频率的数量级在108Hz范围,即在很低的射频区．极化率不应随频率而变化,但是,由于存在核自旋,如H核和F核的核自旋I均为1／2,C1和Br核的核自旋I均为3／2,都会产生核磁场．所以,对HF,HCl和HBr分子,极化率都随频率而增加;而对。He原子,无核自旋,亦无核磁场,所以极化率不随频率而变化．     

Detection of polarization in the cosmic microwave background using DASI. Degree Angular Scale Interferometer

The past several years have seen the emergence of a standard cosmological model, in which small temperature differences in the cosmic microwave background (CMB) radiation on angular scales of the order of a degree are understood to arise from acoustic oscillations in the hot plasma of the early Universe, arising from primordial density fluctuations. Within the context of this model, recent measurements of the temperature fluctuations have led to profound conclusions about the origin, evolution and composition of the Universe. Using the measured temperature fluctuations, the theoretical framework predicts the level of polarization of the CMB with essentially no free parameters. Therefore, a measurement of the polarization is a critical test of the theory and thus of the validity of the cosmological parameters derived from the CMB measurements. Here we report the detection of polarization of the CMB with the Degree Angular Scale Interferometer (DASI). The polarization is deteced with high confidence, and its level and spatial distribution are in excellent agreement with the predictions of the standard theory.     

A velocity dipole in the distribution of radio galaxies

The motion of our Galaxy through the Universe is reflected in a systematic shift in the temperature of the cosmic microwave background-because of the Doppler effect, the temperature of the background is about 0.1 per cent higher in the direction of motion, with a correspondingly lower temperature in the opposite direction. This effect is known as dipole anisotropy. If our standard cosmological model is correct, a related dipole effect should also be present as an enhancement in the surface density of distant galaxies in the direction of motion. The main obstacle to finding this signal is the uneven distribution of galaxies in the local supercluster, which drowns out the small cosmological signal. Here we report a detection of the expected cosmological dipole anisotropy in the distribution of galaxies. We use a survey of radio galaxies that are mainly located at cosmological distances, so the contamination from nearby clusters is small. When local radio galaxies are removed from the sample, the resulting dipole is in the same direction as the temperature anisotropy of the microwave background, and close to the expected amplitude. The result therefore confirms the standard cosmological interpretation of the microwave background.     

地磁场能量在地球内部的三维分布及其长期变化

 利用Bloxham&;Jackson地磁场模型(BJ)和国际地磁参考场模型(IGRF)资料,计算并分析了1690年以来地磁总能量、北向、东向和垂直向分量的能量从CMB到地表的分布和时间变化.结果表明,地磁场总能量以及北向和垂直向分量的能量在地表和地球内部的变化一致,1690年以来减小,东向分量的能量变化以波动形式增大,偶极子磁场能量持续减小.非偶极子磁场的能量1690~1770年减小,1770年以后增大.磁能密度在CMB附近增大较快,地表的磁能密度只有CMB的1.6%.从地表向下至CMB,偶极子和非偶极子的磁能密度的变化相反,偶极子减小,非偶极子增大.     

宇宙微波背景辐射检验CPT对称性

电荷共轭-宇称-时间反演（CPT）联合对称性是粒子物理中的一种基本对称性.检验CPT对称性是检验标准模型及发现新物理等基础科学研究的重要途径.本文将介绍利用高精度的宇宙微波背景辐射（CMB）的观测和实验检验CPT对称性的方法,以及最新进展.通过与其他实验的比较我们发现CMB对CPT对称性的检验精度更高.     

Thermoelectric properties of tungsten ceramics prepared from nanopowder precursors

Tungsten trioxide ceramics were prepared from nm-sized powder precursors. Thermoelectric properties of samples were investigated. The results demonstrated that ceramics prepared in this manner have improved electrical conductivity and Seebeck coefficient values. The power factor of these samples also improved markedly, the largest power factor being 0.027 μW m-1K-2 at 773 K.     

标准加入直读法快速测定南阳彩色小麦中的铜

为建立一种快速测定小麦中微量铜的新方法,选用河南不同地区种植的南阳彩色小麦为样品,微波消解处理后,采用标准加入直读离子选择性电极法测定样品中的微量铜,并对测定条件进行优化.结果表明,Cu2+检出限为0.027 5μg/g,用1.0 mg/L Cu2+标准溶液测定的RSD=7.2%,加标回收率介于90.5%—105.4%(n=11),与国标火焰原子吸收法对照测定无显著性差异.该法具有快速、简便、准确、直观、便于现场直接检测等显著优点,用于样品的快速测定结果令人满意.     

Characterization of the structural details of residual austenite in the weld metal of a 9Cr1MoNbV welded rotor

The existence of residual austenite in weld metal plays an important role in determining the properties and dimensional accuracy of welded rotors. An effective corrosive agent and the metallographic etching process were developed to clearly reveal the characteristics of residual austenite in the weld metal of a 9Cr1MoNbV welded rotor. Moreover, the details of the distribution, shape, length, length-to-width ratio, and the content of residual austenite were systematically characterized using the Image-Pro Plus image analysis software. The results revealed that the area fraction of residual austenite was approximately 6.3% in the observed weld seam; the average area, length, and length-to-width ratio of dispersed residual austenite were quantitatively evaluated to be (5.5 ± 0.1) μm2, (5.0 ± 0.1) μm, and (2.2 ± 0.1), respectively. The newly developed corrosive agent and etching method offer an appropriate approach to characterize residual austenite in the weld metal of welded rotors in detail.     

阻燃剂硼酸锌（2375）的固相合成与表征

为探索一种新的硼酸锌合成路线,针对青海省丰富的硼资源和锌资源,进行了以硼酸、七水硫酸锌和硼砂为原料,在微波辐射下固相合成硼酸锌的实验。考察了配料比、微波辐射强度、微波辐射时间等对产品硼酸锌硼锌比的影响。结果表明：当硼酸与七水硫酸锌的摩尔比为1.0、硼砂与七水硫酸锌的质量比为1.27、微波辐射时间为8 min、微波辐射强度为中低火时合成的硼酸锌为2375型。通过红外光谱、扫描电镜、X射线衍射仪等方法对不加聚乙二醇与加聚乙二醇的两种合成产品进行了表征。结果显示合成的硼酸锌产品呈不规则的片状,加了聚乙二醇的产品平均粒径小于1μm。     

主成分分析法中数据处理方法的改进

由于原有的主成分分析法受到评价指标量纲和数量级的影响，因而主成分也会因评价指标量纲和数量级的改变而不同，并且使得部分信息丢失。用均值化方法借助DPS数据处理软件，对原始数据进行无量纲化处理，不仅有效消除了量纲与数量级的影响，而且使得处理后的数据包含了原始数据的全部信息。     

微波-磷酸一步法制备油茶果壳基活性炭

为了获得农林废弃物油茶果壳制备活性炭的新方法,以磷酸为活化剂,微波内热方式进行炭化-活化一步法制备油茶果壳基活性炭的研究,考察了原料粒度、浸渍比、磷酸浓度、微波时间、微波功率和浸渍时间对活性炭碘吸附性能的影响,并以自制油茶果壳基活性炭为吸附剂进行了茶油毛油脱色。结果表明,油茶果壳基活性炭制备的适宜条件为:原料粒度0.25～0.38 mm,浸渍比1∶2,磷酸浓度60 wt%,微波时间18 min,微波功率700 W,浸渍时间20 h,在最适宜条件下所得活性炭的比表面积为1 169.69 m2/g,脱色茶油的色泽为罗维朋色号黄(Y)11和红(R)1.0,符合国标油茶籽油GB/T 11765-2003对一级油品的色泽技术要求。研究结果可为油茶主副产业链的综合利用提供理论依据。     

激光冲击Johnson-Cook模型材料参数优化

采用Abaqus有限元软件,建立激光冲击718镍铬合金诱发的残余应力场非线性弹塑性有限元模型,实现激光冲击强化残余应力场的数值仿真.通过仿真分析及试验结果对照,说明以Johnson-Cook模型作为本构关系是可行的,激光冲击能形成残余压应力层,提高疲劳寿命,但由于应变率的差异,必须对JC模型材料参数进行优化,才能取得较精确的结果,并从激光功率密度对残余应力场的分析进一步加以验证.结果表明,提出的JC模型材料参数优化方法简单易行.     

微波法提取丁香色素

研究微波法提取丁香中食用色素的最佳工艺条件。方法：称取一定量的备用原料,选取微波功率、辐射时间、提取剂浓度、原料用量（g）与提取剂用量（mL）的配比（料液比）等进行单因素试验与正交试验。结果：微波功率是影响提取丁香色素的主要因素;影响丁香色素提取的顺序是微波功率〉料液比〉辐射时间〉提取剂浓度;最优工艺条件是微波辐射功率为500 W,辐射时间为120 s,提取剂为20%乙醇溶液,料液比为1 g：8 mL;提取液浓度与料液比之间存在交互作用。结论：正交试验是省时省力、结果易得的实用方法。     

共线改进的色玻璃凝聚理论中矢量介子产生研究

将利用共线改进的并以靶快度作为演化变量的偶极子散射振幅研究高能电子－质子散射中矢量介子的产生.研究中首先采用数值方法求解描述偶极子靶快度演化的微分积分方程,得到数值形式的偶极子散射振幅;然后,把该散射振幅放入矢量介子产生的微分截面中,用于拟合HERA实验数据.为了比较,分别采用了领头阶和共线改进的次领头阶偶极子散射振幅拟合J/ψ和两种矢量介子的实验数据,通过拟合分别得到在领头阶的情况下χ2/d.o.f＝1.485(J/ψ)、χ2/d.o.f＝1.696()和共线改进的情况下χ2/d.o.f＝0.996(J/ψ)、χ2/d.o.f＝1.089().研究结果表明共线改进的以靶快度作为演化变量的偶极子散射振幅能更好的描述实验数据.     

A broadband superconducting detector suitable for use in large arrays

Cryogenic detectors are extremely sensitive and have a wide variety of applications (particularly in astronomy), but are difficult to integrate into large arrays like a modern CCD (charge-coupled device) camera. As current detectors of the cosmic microwave background (CMB) already have sensitivities comparable to the noise arising from the random arrival of CMB photons, the further gains in sensitivity needed to probe the very early Universe will have to arise from large arrays. A similar situation is encountered at other wavelengths. Single-pixel X-ray detectors now have a resolving power of DeltaE < 5 eV for single 6-keV photons, and future X-ray astronomy missions anticipate the need for 1,000-pixel arrays. Here we report the demonstration of a superconducting detector that is easily fabricated and can readily be incorporated into such an array. Its sensitivity is already within an order of magnitude of that needed for CMB observations, and its energy resolution is similarly close to the targets required for future X-ray astronomy missions.     

源解析NKCMB最优拟合法及其实现

在大气颗粒物源解析领域中,在一套数据中由于选择不同的拟合源和拟合组分,CMB模型会产生多个解析结果。提出了NKCMB最优拟合法,解决现存的CMB模型在所限定的条件内不能穷举所有的解析结果以及在众多的结果中人工择优的局限等问题。基于NKCMB最优拟合法和美国环保总署提供的EPA-CMB8.2软件开发了NKCMB3.0软件。使用美国环保总署提供的测试数据进行的对比试验证明,NKCMB最优拟合法能够找到比EPA-CMB8.2的Best Fit更优的源解析结果。     

Measurement of polarization with the Degree Angular Scale Interferometer

Measurements of the cosmic microwave background (CMB) radiation can reveal with remarkable precision the conditions of the Universe when it was approximately 400,000 years old. The three most fundamental properties of the CMB are its frequency spectrum (which determines the temperature), and the fluctuations in both the temperature and polarization across a range of angular scales. The frequency spectrum has been well determined, and considerable progress has been made in measuring the power spectrum of the temperature fluctuations. But despite many efforts to measure the polarization, detection of this property of the CMB has hitherto been beyond the reach of even the most sensitive observations. Here we describe the Degree Angular Scale Interferometer (DASI), an array of radio telescopes, which for the past two years has conducted polarization-sensitive observations of the CMB from the Amundsen-Scott South Pole research station.