Efficient and rapid accuracy estimation of the Earth’s gravitational field from next-generation GOCE Follow-On by the analytical method

Firstly, a new analytical error model of the cumulative geoid height using the three-dimensional diagonal tensors of satellite gravity gradiometry (SGG) is introduced based on the variance-covariance matrix principle. Secondly, a study for the requirements demonstration on the next-generation GOCE Follow-On satellite gravity gradiometry system is developed using different satellite orbital altitudes and measurement accuracies of satellite gravity gradiometer by the new analytical error model of SGG. The research results show that it is preferable to design satellite orbital altitudes of 300 km-400km and choose the measurement accuracies of 10-13/s2 -10-15/s2 from satellite gravity gradiometer. Finally, the complementarity of the four-stage satellite gravity missions, including past CHAMP, current GRACE, and GOCE, and next-generation GOCE Follow-On, is contrastively demonstrated for precisely recovering the Earth’s full-frequency gravitational field with high spatial resolution.     

惰气熔融-红外法测定镍钛合金中的氧含量

针对镍钛(NiTi)合金中的氧含量进行研究,建立了惰气熔融-红外吸收法测定NiTi合金中氧含量的新方法。研究了不同助熔剂、称样量、分析功率、分析时间及比较器水平对测定结果的影响。确定采用镍做助熔剂,分析功率为4.0至5.5kW,分析时间为30s,比较水平为2的条件对NiTi合金中氧含量进行测定。惰气熔融-红外法测定NiTi合金氧含量相对标准偏差为1.8%,对标准样品的测定结果与标准值基本相符。方法操作简单,分析速度快,能满足生产要求,对工艺研究和产品质量控制具有积极意义。     

Ce(Ⅳ)-Ru(bpy)_3~(2+)化学发光体系测定利塞膦酸钠

在酸性介质中,利塞膦酸钠对Ce(Ⅳ)-Ru(bpy)32+化学发光体系有显著的增强作用,据此建立了静态注射化学发光法测定利塞膦酸钠的新方法。在优化的实验条件下,其测定范围在1.0～20.0 mg/L,检出限为0.6 mg/L,对10.0 mg/L样品进行11次平行测定,RSD为2.2%。     

A Geometrical Model for Tortuosity of Tortuous Streamlines in Porous Media with Cylindrical Particles

We present a three-dimensional geometry model for tortuosity of streamlines in porous media with randomly placed cylindrical particles. The proposed model is expressed as functions of porosity and geometrical parameters with no empirical constant. This might be helpful for understanding the physical mechanism for tortuosity of streamlines in three-dimensional porous media. The model predictions are found to be in good agreement with the experimental data available.     

Photoluminescence and X-Ray Photoelectron Spectroscopy of p-Type Phosphorus-Doped ZnO Films Prepared by MOCVD

Reproducible p-type phosphorus-doped ZnO （p-ZnO：P） films are prepared on semi-insulating InP substrates by metal-organic chemical vapour deposition technology. The electrical properties of these films show a hole concentration of 9.02 × 10^17 cm ^-3, a mobifity of 1.05 cm^2 /Vs, and a resistivity of 6.6 Ω.cm. Obvious acceptorbound-exciton-related emission and P-induced zinc vacancy （Vzn） emission are observed by low-temperature photoluminescence spectra of the films, and the acceptor binding energy is estimated to be about 125meV. The local chemical bonding environments of the phosphorus atoms in the ZnO are also identified by x-ray photoelectron spectra. Our results show direct experimental evidence that Pzn-2Vzn shallow acceptor complex most likely contributes to the p-type conductivity of ZnO：P films.     

A contrastive study on the influences of radial and three-dimensional satellite gravity gradiometry on the accuracy of the Earth's gravitational field recovery

The accuracy of the Earth’s gravitational field measured from the gravity field and steady-state ocean circulation explorer(GOCE),up to 250 degrees,influenced by the radial gravity gradient V zz and three-dimensional gravity gradient V ij from the satellite gravity gradiometry(SGG) are contrastively demonstrated based on the analytical error model and numerical simulation,respectively.Firstly,the new analytical error model of the cumulative geoid height,influenced by the radial gravity gradient V zz and three-dimensional gravity gradient V ij are established,respectively.In 250 degrees,the GOCE cumulative geoid height error measured by the radial gravity gradient V zz is about 2 1/2 times higher than that measured by the three-dimensional gravity gradient V ij.Secondly,the Earth’s gravitational field from GOCE completely up to 250 degrees is recovered using the radial gravity gradient V zz and three-dimensional gravity gradient V ij by numerical simulation,respectively.The study results show that when the measurement error of the gravity gradient is 3×10 12 /s 2,the cumulative geoid height errors using the radial gravity gradient V zz and three-dimensional gravity gradient V ij are 12.319 cm and 9.295 cm at 250 degrees,respectively.The accuracy of the cumulative geoid height using the three-dimensional gravity gradient V ij is improved by 30%-40% on average compared with that using the radial gravity gradient V zz in 250 degrees.Finally,by mutual verification of the analytical error model and numerical simulation,the orders of magnitude from the accuracies of the Earth’s gravitational field recovery make no substantial differences based on the radial and three-dimensional gravity gradients,respectively.Therefore,it is feasible to develop in advance a radial cold-atom interferometric gradiometer with a measurement accuracy of 10 13 /s 2-10 15 /s 2 for precisely producing the next-generation GOCE Follow-On Earth gravity field model with a high spatial resolution.     

不同类型土壤总氮的近红外光谱技术测定研究

该研究从江苏、河南、山西、河北、吉林采集部分表层土壤,并在山西河北两地采集表下层土壤,经前处理后通过近红外光谱仪扫描得到光谱图,用传统开氏法测得其总氮,运用OPUS软件建立了土壤总氮和光谱图之间的数学模型,并初步探讨了模型的应用范围。结果表明：各地区表层土壤建立的模型良好,交叉检验的均方根误差均在0.01%以内,相关系数平均在0.85以上,并且该模型能够很好地定量分析同一采样范围内表层和表下层的土壤总氮,定量分析的均方根误差基本在0.01%以内,相关系数在0.80左右;可能受土壤类型的影响,该模型在地区之间的运用具有一定的局限性;从各地区随机取出部分数据作为一个新的集合建立的综合模型良好,其交叉检验的均方根误差和相关系数分别为0.010 2%和0.985 6,并且该模型能很好地预测各地区的土壤总氮。     

谷胱甘肽亲和色谱介质的制备及对谷胱甘肽硫转移酶蛋白的纯化

融合表达系统能够为目标蛋白质提供一个用于亲和色谱纯化的标签蛋白,同时可以改善目标蛋白质的可溶性等性质,谷胱甘肽S转移酶(GST)融合蛋白表达系统就是其中的一种。然而,该系统纯化所采用的亲和色谱介质的制备技术被国外一些生物制品大公司所垄断。鉴于此,本实验室通过悉心研究,摸索出一套较成熟的亲和色谱介质的制备方法。     

氧化锌单晶生长、载流子调控与应用研究进展

氧化锌(ZnO)是一种历史悠久的材料,由于其微观结构非中心对称,最初被预测可以应用于压电和非线性光学领域,又因为它在室温下具有宽的禁带和高的激子束缚能,是一类重要的第三代宽禁带半导体材料,在半导体领域受到了广泛关注。然而,在实际应用中,ZnO在上述各个领域都遇到了一些瓶颈问题:在压电领域,原本被认为是绝缘的ZnO出现了意外的导电性;在非线性光学领域,ZnO的折射率差很小,难以获得好的相位匹配;在半导体领域,难以同时获得高载流子浓度、高迁移率、高热稳定性的p型ZnO。本文主要针对以上ZnO的应用前景及相关瓶颈问题进行了总结,并提出了适用于离子型化合物半导体的载流子调控普适性理论,即:载流子类型完全由材料的精细化学组分完整表达式来决定。这一规则将原本被认为是无关的材料精细化学组分完整表达式和载流子类型两个概念联系起来,在认识上具有很大的突破,并形成了材料科学研究的新范式。该范式成功指导了高绝缘和高热稳定性的n型ZnO单晶以及高迁移率掺Al∶ZnO薄膜的生长,并为高载流子浓度、高迁移率、高热稳定性p型ZnO的制备提供了新思路。近来,除了上述应用领域外,ZnO还被发现在超快闪烁体和中红外(MIR)透明导电窗口领域具有较大的应用贡献,并推测这些领域很可能领先于ZnO原本受到重视的研究领域而取得真正的应用进展。     

面向脉冲星导航的聚焦型X射线探测器测试标定方法研究

通过脉冲星辐射信号特征研究和空间观测需求分析,提出了一种面向导航应用的X射线探测器测试方法.首先推导了X射线光子欠探测概率公式,分析了不同星源流量及不同探测器时间分辨率下对光子探测能力的影响.通过数值模拟方法建立了脉冲到达时间与脉冲轮廓相似度的关系.处理了我国硬X射线调制望远镜的Crab脉冲星观测数据,研究了不同能段脉冲轮廓差异.其次,系统地研究了面向导航应用的X射线探测器测试及处理方法,并利用地面测试系统完成了一款自主研发的聚焦型X射线探测器测试工作.通过数据分析得到,聚焦型探测器本底噪声为3.63×10-5ph/(cm~2·s~(-1)),工作能区为0.2～22.7keV,时间分辨率为4.17μs,空间响应约为5′,能量非线性为0.52%,能量分辨率优于200eV@5.7keV,典型探测效率为39.18%@4.51keV.聚焦型X射线探测器在弱脉冲信号及强背景噪声下,均能还原出Crab脉冲星脉冲轮廓,在2 400s内能够探测到辐射流量弱于背景噪声10倍的脉冲信号.结果表明,该款聚焦型探测器性能优秀,能够满足导航脉冲星(如PSR B1509)的空间观测需求,也验证了测试方法的可行性.