合成磷灰石的去氟机理研究          下载免费PDF全文

黄志良  刘羽  王大伟  张术根  陈露军 《岩石矿物学杂志》2001,20(4):568-572

用固相反应法和sol-gel法合成了不同类型的磷灰石（AP），并采用TEM、XRD、IR、BET比表面积法及静、动态吸附等方法研究了不同AP的比表面积、结晶度、晶胞参数、结晶尺寸、晶格缺陷度、Ca/P摩尔比和煅烧温度等与吸氟能力的关系，结果表明：结晶度高、晶粒大的AP有较小的吸氟量，属表面单分子层化学络合吸附机理；酸活化的AP有较大的吸氟量，属溶解-沉淀与沉淀物表面纳米尺寸效应吸附的复合去氟机理；具纳米尺寸的HAP在常温、常压、无二次污染、小于11mg/L的低含氟浓度废水中且不酸化情况下有较大吸氟量，属纳米尺寸效应吸附机理。  相似文献   

Dynamical problem of micropolar viscoelasticity     

Rajneesh Kumar  Suman Choudhary 《Journal of Earth System Science》2001,110(3):215-223

The dynamic problem in micropolar viscoelastic medium has been investigated by employing eigen value approach after applying Laplace and Fourier transformations. An example of infinite space with concentrated force at the origin has been presented to illustrate the application of the approach. The integral transforms have been inverted by using a numerical technique to obtain the displacement components, force stresses, couple stress and microrotation in the physical domain. The results for these quantities are given and illustrated graphically.  相似文献   

一种气候预测综合决策的方法——递归正权综合决策法   总被引：2，自引：0，他引：2  

项静恬  陈国珍  刘海波  赵振国 《大气科学》1999,23(5):551-558

根据气候预测的特点，提供了以误差平方和为风险函数，以正权综合为模式的多途径气候预测决策方案。不仅从理论上论证了几种正权方法的优性，还提供了递归技巧，进一步提高了正权综合的预测精度。对1997年汛期降水预测所做的综合决策表明，该方法具有较好的综合决策能力。  相似文献   

Measurements of stratospheric chlorine monoxide (ClO) from groudbased FTIR observations     

W. Bell  C. Paton-Walsh  T. D. Gardiner  P. T. Woods  N. R. Swann  N. A. Martin  L. Donohoe  M. P. Chipperfield 《Journal of Atmospheric Chemistry》1996,24(3):285-297

Infrared absorption features due to ClO in the lower stratosphere have been identified from groundbased solar absorption spectra taken from Aberdeen, U.K. (57° N, 2° W) on 20 January 1995. A vertical column abundance of 3.42 (±0.47)×10¹⁵ molec cm^-2 has been derived from 13 independent absorption features in the P and R branches of the (0–1) vibration-rotation band of ³⁵ClO, spanning the spectral region 817–855 cm^-1. The observed absorption features are consistent with very high levels of ClO (approximately 2.6 parts per billion by volume (ppbv)) in the altitude range 16–22 km. A comparison of this profile with a 3D chemical transport model profile indicates the observation was made inside the polar vortex and shows good qualitative agreement but the model underestimates the concentrations of ClO. Simultaneous measurements of other species were made including HCl, HF and ClONO₂. These columns yield a value for HCl+ClONO₂+ClO of 7.02±0.65×10¹⁵ molec cm^-2. This is lower than the total inorganic chlorine (ClO _y ) column of 10.7±1.6×10¹⁵ molec cm^-2 estimated from mean measured (HCl+ClONO₂)/HF ratios together with in-vortex HF measurements. The discrepancy is probably due to significant amounts of the ClO dimer (Cl₂O₂) in the lower part of the stratosphere. The measurements of highly elevated levels of ClO are used to estimate O₃ loss rates at the 400, 475 and 550 K levels making assumptions about the probable distribution of ClO and Cl₂O₂. These are compared with loss rates derived from ozone sonde data.  相似文献   

高强度粗颗粒金刚石的合成技术研究     

王松顺  王民 《煤田地质与勘探》1992,20(2):68-70,F003

在高温高压下,六方晶格的石墨转变为立方晶格的金刚石。选用灰分含量少、气孔分布均匀的T621A石墨为碳源,选择化学成分范围偏值小、杂质含量少的镍锰钴合金为触媒以及优质粉压叶腊石为传压介质,在高温、适压、长时间及其它条件下,合成高强度粗颗粒的优质金刚石取得了良好的效果。  相似文献   

关于数字相位式测距仪的频率改正     

徐忠阳 《测绘学院学报》1995,(4)

本文在分析自动脉冲数字测相基本原理的基础之上，推出了不仅与测距频率有关，而且还与填充脉冲频率及低频测相频率有关的新的频率改正公式，并给出新的频率改正公式与传统频率改正公式之间等同的条件，即有锁相环路（或频率跟踪电路）的正常工作来保证。  相似文献   

从灰度变化获取表面形状的研究     

王新华  傅晓云 《武汉大学学报(信息科学版)》1995,(3)

提出了一种基于可信度操作的从灰度变化信息获取表面形状的方法，并结合在频率域的强制可积约束，把对表面梯度空间（ｐ，ｑ）的处理经过高斯球变换到（ｆ，ｇ）空间处理，不仅较好地保证了算法的收敛性和可靠性，而且有利于边界条件的确定。  相似文献   

探地雷达图象的正演合成   总被引：5，自引：0，他引：5  

邓世坤 《地球科学》1993,18(3):285-293

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Detection, excision and statistics of interference at the Mauritius radio telescope     

S. Sachdev  N. Udaya Shankar 《Journal of Astrophysics and Astronomy》2001,22(2-3):213-227

A technique to detect man-made interference in the visibility data of the Mauritius Radio Telescope (MRT) has been developed. This technique is based on the understanding that the interference is generally ‘spiky’ in nature and has Fourier components beyond the maximum frequency which can arise from the radio sky and can therefore be identified. We take the sum of magnitudes of visibilities on all the baselines measured at a given time to improve detectability. This is then high-pass filtered to get a time series from which the contribution of the sky is removed. Interference is detected in the high-pass data using an iterative scheme. In each iteration, interference with amplitudes beyond a certain threshold is detected. These points are then removed from the original time series and the resulting data are high-pass filtered and the process repeated. We have also studied the statistics of the strength, numbers, time of occurrence and duration of the interference at the MRT. The statistics indicate that most often the interference excision can be carried out while post-integrating the visibilities by giving a zero weight to the interference points.  相似文献   

On smoothing techniques for the removal of periodic noise of known period     

R. S. Anderssen  E. Seneta 《Mathematical Geology》1971,3(2):157-170

This paper is concerned with the analysis of the linear modely(n)=X(n)+S(n)+(n) for the data sequencey(n) (n=1, 2, ..., N) whereX={x _IJ} is a knownJ × M matrix of full rankM. Here, the(n) are unknown vectors, which we wish to estimate for eachn; S(n) (n=1, 2, ..., N) is a periodic component (which we wish to estimate or remove) superimposed on the linear structureX(n); and(n) is an error vector which is specified as having zero expectation (with possible further properties). Such models commonly occur in geophysical data analysis.Modified from Technical Report No. 33, Computer Centre, The Australian National University.  相似文献