基于阈值光电子-光离子符合技术的分子离子光谱和解离动力学研究

对电子和离子同时采用速度聚焦电场收集的阈值光电子-光离子符合成像谱仪能够有效提高电子的收集效率和能量分辨率.利用该符合成像谱仪,开展了Xe/Ar/Ne 惰性混合气体及NO 分子的阈值光电子谱、阈值光电子-光离子符合质谱和质量选择的符合光谱等实验研究,精确测量了NO 分子的电离势,并且获得了NO⁺离子振动态分辨的X¹Σ⁺,c³Π和B¹Π态光谱.还进一步研究了NO^{+ 相似文献}   

Inflorescences of Mauldinia sp. (Lauraceae) and associated fruits from the Cenomanian of Languedoc Roussillon,France

Inflorescences of Mauldinia (Lauraceae) are described from the middle Cenomanian Pauletian facies of Gard, Languedoc-Roussillon, south-eastern France. This is the first record of the genus from this part of Europe. Mauldinia sp. is described based on peduncles and lateral units. Isolated, slender peduncles show spirally arranged scars or rarely attached lateral units. Isolated lateral units consist of cladode-like structures showing up to seven flower/fruit scars. Some isolated fruits were found associated with peduncles and lateral units. Fruits are ovoid fruits contain a single, elongated seed. The pericarp consists of epicarp, mesocarp and endocarp. The seed consists of two cotyledons containing well-developed reserve cells. Mauldinia sp. from Gard differs from known Mauldinia species by having longer internodes along the peduncle and by the shape of the lateral units. Sedimentological and palaeontological evidence suggests that Mauldinia sp. from Gard grew in a protected, littoral environment with limited marine influence. This report provides new information to the relatively poorly known Cretaceous record of angiosperms in France. The occurrence of Mauldinia in the lower Upper Cretaceous of Gard corroborates the widespread occurrence of the genus in marginal littoral environments during the mid-Cretaceous.     

Neutron Activation Analysis, Atomic Absorption and X-Ray Fluorescence Spectrometry Review for 2004–2005

These technologically mature techniques occupied a stable to modestly increasing sector of the spectrum of analytical methods in Earth and environmental sciences in 2004–5. Despite this, several notable advances were reported in this two year period. In the field of X-ray fluorescence spectrometry, these included the development of portable synchrotron and total reflection instruments, the use of pyroelectric crystals as X-ray generators, introduction of high-purity Ge detector arrays, and the development of an XRF imaging spectrometer with the capability of mapping analytes and X-ray intensity ratio. Atomic absorption s spectrometry saw major work published on high-resolution continuum source AAS (HR-CS AAS) involving the development of a xenon short-arc lamp. Other advances included the use of laser wave mixing in a graphite furnace tube (with a claimed detection limit of 10–¹⁶ g g-¹), solid sampling and ultrasound in sample preparation. Neutron activation analysis saw two innovations that may herald future growth in this technique, namely a neutron source free of a nuclear reactor and a detector operating at room temperature.     

The redshift dependence of spectral index in powerful radio galaxies

We present and discuss in this paper the rest frame radio spectra (1–25 GHz) of a sample of fourteen radio galaxies atz >2 from the newly defined MRC/1Jy complete sample of 558 radio sources. These galaxies are among the most powerful radio sources known and range in luminosity from 1028-1028·8 watt Hz-1 at 1 GHz. We find that the median rest frame spectral index of this sample of galaxies atz >2 is significantly steeper than that of a matched luminosity sample of 3CRR galaxies which are at a much lower redshift (0.85 <z < 1.7). This indicates that spectral index correlates primarily with redshift, at least in the luminosity range considered here. The difference between the distributions of rest frame spectral curvatures for the two samples does not appear to be statistically significant. We suggest a new explanation for the steeper spectra of radio galaxies at high redshift involving steeper electron energy spectra at injection. Electron energy spectra are expected to steepen in a first-order Fermi acceleration process, at both non-relativistic and relativistic shock fronts, as the upstream fluid velocity decreases. This may well be the case at high redshifts: the hotter and denser circum-galactic medium at high redshifts could result in slower speeds for the hotspot and the jet material behind it. The smaller sizes of radio sources at higher redshifts provide support to this scenario. Since deceased.     

同步辐射X射线微探针研究宝石矿物成色与某些微量元素的关系

利用北京正负电子对撞机（ＢＥＰＣ）提供的同步辐射（ＳＲ）白光为激发源（束斑尺寸１００μｍ×１００μｍ，计数时间１００ｓ／点），研究了蓝宝石、红宝石、紫晶、祖母绿的天然、加工和合成品的微量元素成分，对于鉴别宝石提供了有益的信息。     

古琉璃着色元素的同步辐射X荧光分析

用同步辐射X射线荧光对陕西不同年代和地层出土的各色古琉璃釉中的主量和微量元素进行了分析，用SPSS统计软件对实验数据进行多元统计分析。结果表明，各色琉璃釉中主要着色元素是Fe、Cu和Co，琉璃中的多样釉色是由三种主要着色元素的含量决定。元素相关性分析表明，Fe和Co可能来自一种原料，而Cu可能来自另一种原料。     

十字石的原位高压X射线衍射研究

利用原位高压同步辐射能量色散X射线衍射技术,在室温下对采自新疆阿尔泰地区冲乎尔递增变质带的天然十字石进行高压晶体结构测定,测量的压力范围为0.0001~3.9GPa,共11组有效数据。实验表明,在实验压力范围内,随着压力的增加晶胞参数β值逐渐增大,表明了十字石的结构对称性随压力增加而有所降低;同时,在1.5~2.7GPa压力范围内,十字石的晶体结构也发生了改变。     

磷灰石单晶体同步辐射X射线荧光探针成分分析

采用同步辐射X荧光（SRXRF）探针技术对河北峪耳崖和甘肃大水两地花岗岩中单颗粒磷灰石的化学成分进行了分析。结果显示，磷灰石含有P、Cl、S、K、Ca、Mn、Fe、La、Ce、Nd、Sm、Gd、Yb、Sr、Y、Zr、U、Th等多种元素，峪耳崖磷灰石富含Mn、Fe，大水磷灰石则富含As。峪耳崖花岗岩为S型，大水花岗岩为Ⅰ型，两地磷灰石在稀土元素（REE）含量上具有明显差别：大水磷灰石呈右倾的REE配分模式和明显的轻稀土（LREE）富集；而峪耳崖呈现上凸的REE配分模式和LREE亏损。依据磷灰石的REE配分模式可有效地区分不同类型的花岗岩，以此作为花岗岩岩浆演化的指示。     

Atmospheric loss of energetic electrons in the Jovian synchrotron zone

For decades, ground-based radio observations of Jovian synchrotron radiation have shown emission originating predominantly from the equatorial region and from high-latitude regions (lobes) near L∼2.5. The observations show a longitudinally asymmetric gap between the emission peaks of the lobes and the atmosphere of Jupiter. One possible explanation for these gaps is the loss of electrons through collisions with atmospheric neutrals as the electrons bounce along magnetic field lines and drift longitudinally in the presence of asymmetric magnetic fields. To assess this hypothesis, we applied the recently developed O6 and VIP4 magnetic field models to calculate the trajectories of electrons as they drift longitudinally in Jupiter's magnetic field, and derive the sizes of their equatorial drift loss cones. We then identified the shells on which electrons would be lost due to collisions with the atmosphere. The calculated drift loss cone sizes could be applied in future to the modeling of electron distribution functions in this region and could also be applied to the study of Jovian auroral zone. This method also allowed us to compute the shell-splitting effects for these drifting electrons and we find the shell-splitting to be small (?0.05R_J). This justifies a recent modeling assumption that particles drift on the same shells in a three-dimensional distribution model of electrons. We also compared the computed gaps with the observed gaps, and found that the atmospheric loss mechanism alone is not able to sufficiently explain the observed gap asymmetry.     

Preferred mineral orientation of a chloritoid-bearing slate in relation to its magnetic fabric

A regional analysis of the anisotropy of the magnetic susceptibility on low-grade metamorphic, chloritoid-bearing slates of the Paleozoic in Central Armorica (Brittany, France) revealed very high values for the degree of anisotropy (up to 1.43). Nonetheless, high-field torque magnetometry indicates that the magnetic fabric is dominantly paramagnetic. Chloritoid's intrinsic degree of anisotropy of 1.47 ± 0.06, suggests that chloritoid-bearing slates can have a high degree of anisotropy without the need of invoking a significant contribution of strongly anisotropic ferromagnetic (s.l.) minerals. To validate this assumption we performed a texture analysis on a representative sample of the chloritoid-bearing slates using hard X-ray synchrotron diffraction. The preferred orientation patterns of both muscovite and chloritoid are extremely strong (∼38.6 m.r.d. for muscovite, 20.9 m.r.d. for chloritoid) and display roughly axial symmetry about the minimum magnetic susceptibility axis, indeed suggesting that chloritoid may have a profound impact on the magnetic fabric of chloritoid-bearing rocks. However, modeling the anisotropy of magnetic susceptibility by averaging single crystal properties indicates that the CPO of chloritoid only partially explains the slate's anisotropy.