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21.
22.
为了给双星计划中性原子(ENA)探测仪的研制提供可靠 的理论依据,并为未来中性原子探测数据的分析及研究做好准备,针对双星轨道初步模拟计 算了双星ENA探测仪对磁暴时中性原子的观测特性. 建立了磁暴主相期间环电流离子分布的 一 个近似理论模式,并模拟计算了极轨卫星在极区上空、赤道面以及其他位置上对不同强度磁 暴主相期间环电流区ENA空间角分布及能谱的观测结果. 研究表明,存在环电流区方向和南 北极区环电流粒子沉降带两个中性原子强度极大区域;磁暴越强烈,注入区高度越低,环电 流区观测到的ENA通量越高;处于有利位置的ENA探测器可分辨注入区内边界或注入前沿;EN A探测器能够分辨环电流带离子分布的不均匀性;由于离子交换截面的差异,H,O,He 3种E NA的能谱分布不同;在10~80keV能谱范围内通量较强,易于观测;环电流区H,O两种ENA 通 量较强,有利于观测;而环电流区He ENA通量很弱,不易于观测. 模拟计算研究表明,双星 极轨卫星能够对环电流区ENA进行有效探测;低纬轨道上的ENA探测器也能够对环电流区ENA 进行一些观测;ENA探测器的研制应重视低、中能量范围ENA的探测. 相似文献
23.
柱撑蒙脱石制备与表征 总被引:47,自引:2,他引:47
本文采用多种方法制备keggin离子,并探索出制备稳定keggin离子的适宜酸碱度,用此柱化剂制备出层间距为2.4~2.5nm的柱撑蒙脱石。应用X射线走向衍射技术、红外光谱、差热分析对往撑蒙脱石进行表征,用BET、吡啶吸附考察了其表面物理化学性质。结果表明,用Keggin离子制备出的柱撑蒙脱石其层间距在自然状态下为2.4~2.5nm,350C灼烧,层间距稳℃定在1.8nm,且具有耐热性能好、较大的比表面积和较强的Lewis酸位中心等特点. 相似文献
24.
25.
The application of X-ray photoelectron spectroscopy (XPS) to coal surface characterisation for preparation research is described. Progress towards the acquisition of complementary surface chemical information by time-of-flight secondary ion mass spectrometry (ToF-SIMS) is also discussed. Surface-based beneficiation techniques such as flotation are assuming greater importance as the proportion of fines in raw coal increases due to the proliferation of high capacity mining methods. A necessary condition for the floatability of a coal particle is adequate hydrophobicity, and the degree of hydrophobicity of the flotation concentrate is one factor influencing the ease with which its dewatering can be affected. The hydrophobicity of a coal is very difficult to measure directly because of microporosity, and it is often necessary to deduce the degree of hydrophobicity from a knowledge of the surface chemistry. XPS is able to provide sufficient analytical data to allow relative levels of hydrophobicity to be estimated. In principle, ToF-SIMS should be able to supply additional information enabling refinement of such estimates; however, there are insufficient data at present to allow the ionic fragments detected to be related to specific functional groups at the coal surface. 相似文献
26.
在分散度不同的区域内进行区域采样用于水中硫酸根离子的测定,结果令人满意。应用此方法测定硫酸根离子的线性范围为200.0~3000mg/L;进样频率为120次/h;相对标准偏差为1.70% 相似文献
27.
High-pressure, high-temperature diamond growth experiments have been conducted in the system C–K2CO3–KCl at 1050–1420 °C, 7.0–7.7 GPa. KCl is of interest because of the strong effect of halogens on the phase relations of carbonate-rich systems [Geophys. Res. Lett. 30 (2003) 1022] and because of the occurrence of KCl coexisting with alkali silicate–carbonate fluids in natural-coated diamond [Geochim. Cosmochim. Acta 64 (2000) 717]. We have used system C–K2CO3–KCl as an analogue for these mantle fluids in diamond growth experiments. The presence of KCl reduces the potassium carbonate liquidus to ≤1000 °C at 7.7 GPa, allowing it to act as a solvent catalyst for diamond growth at temperatures below the continental geotherm. This is a reduction on the minimum diamond growth temperature reported in the alkali-carbonate–C–O–H system [Lithos 60 (2002) 145]. Diamond growth using carbonate solvent catalysts is characterised by a relatively long induction period. However, the addition of KCl also reduced the period for diamond growth in carbonate to 5 min; no such induction period appears to be necessary. It is suggested that KCl destabilises carbonate, allowing greater solubility and diffusion of carbon. 相似文献
28.
Yin Xiulan China Institute of Geo-environmental Monitoring Beijing China Hu Ping Faculty of Earth Sciences China University of Geosciences Wuhan China Northeastern Illinois University Chicago IL USA Li Dien Division of Earth Environmental Sciences Los Alamos National Laboratory Los Alamos NM USA 《中国地质大学学报(英文版)》2004,15(4):355-360
The sorption of Eu species onto nano-size silica-water interfaces was investigated using fluorescence spectroscopy for Ph ranges of 1-8.5 and an initial Eu concentration (Ceu) of 2×10-4 M. The sorption rate of Eu was initially low, but significantly increased at Ph>4. The sorption density of Eu species on a silica surface was ~1.58×10-7 mol/m2 when the dissolved Eu species were completely sorbed onto silica-water interfaces at Ph=~5.8. The sorbed Eu species at Ph<6 is aquo Eu3 , which is sorbed onto silica-water interfaces as an outer-sphere complex at Ph<5, but may be sorbed as an inner-sphere bidentate complex at 5相似文献
29.
S. Y. Fu Q. G. Zong Z. Y. Pu C. J. Xiao A. Korth P. Daly H. Reme 《Surveys in Geophysics》2005,26(1-3):241-254
In this paper we report energetic ion behavior and its composition variations observed by the Cluster/RAPID instrument when the spacecraft was travelling in the high latitude magnetospheric boundary region on the day of the 31 March, 2001, strongest magnetic storm in the past 50 years. The Dst index reached −360 nT at about 09:00 UT. During its early recovery phase, large amounts of oxygen and helium ions were observed; the ratio of oxygen to hydrogen in the RAPID energy range reached as high as 250%, which suggests that the observed energetic particles might be of magnetospheric origin. The observations further show that enhanced energetic electron fluxes are confined in a very narrow region, while protons have occupied a larger region, and heavy ions have been observed in an even larger region. The flux of energetic electrons show a slight enhancement in a region where the magnetic field magnitude is around zero. These observed energetic ions could be quasi-trapped by the current sheet in the stagnation region of the cusp. 相似文献
30.
Water soluble components of PM10 Chongqing, China 总被引:1,自引:0,他引:1
The concentrations of water soluble ions (Na+, NH4
+, K+, Mg2+, Ca2+, NO3
-, Cl-, and SO
4
2-
) in PM10 samples collected on cellulose filters by a medium-volume cascade impactor were determined, which were obtained from three
kinds of areas in Chongqing: industrial area (Jiulongpo district), commercial and residential area (Jiangbei district) and
background area (Jinyun Mountain in the Beibei district). The results showed that except for the background site, the annual
average values of PM10 are 23% – 61% higher than the national air quality standard (GradeII) (0.1 mg/m3), even that the value of the control site is still 20% higher than American standard (0.05 mg/m3). This implied that serious pollution of fine particles occurred in Chongqing. Nine kinds of soluble ions in water of PM10 were analyzed by ion chromatography (IC) and the annual average concentrations follow the order of [SO
4
2-
] > [NO3
-] > [Cl-] > [F-], and [Ca2+] > [NH4
+] > [K+] > [Na+] > [Mg2+]. Their values were different in these areas: the industrial area > the commercial and living area > the control area. As
for NH4
+, K+, Ca2+, NO3
- and SO
4
2-
, their seasonal average concentrations show a similar variation trend: the values in spring and fall were higher than those
in summer and winter. The seasonal average concentrations of [Cl-], [F-], [Na+] and [Mg2+] are much lower than those of other ions. However, the concentrations of [Na+] changed more greatly in different seasons than those of the other three ions. Correlation coefficients showed that the three
areas have been polluted by coal smoke and dust to different extents, while some local resources of pollution should be taken
into consideration as well. 相似文献