PIXE as a complement to trace metal analysis of sediments by ICP-OES

The adverse effects of metal contamination in sediments require methods that can quickly and accurately assess the extent of environmental pollution. Particle induced X-ray emission spectrometry (PIXE) is demonstrated to be a viable alternative to an established method, which consists of acid digestion and Inductively coupled plasma-optical emission spectrometry (ICP-OES) to measure trace metals in sediment. The analysis of trace metal composition by both techniques on a NIST Standard Reference Material mud gives results that are consistent with the certified values for fourteen measured metals, seven of which are common to both methods. A comparison study conducted on a sediment core from a freshwater lake with a known chromium contamination in Muskegon County, MI also shows a good correlation between the methods for transition metals of environmental interest over a wide range of metal concentrations. Total sample preparation and analysis time for the PIXE measurements is roughly one third that of acid digestion and ICP-OES. Also, the acid digestion step does not elute all the metal, while the nondestructive PIXE approach is a total metals analysis method. However the PIXE method generally has higher limits of detection for many environmental metal contaminants. By combining the two techniques, the acid digestion elution factor can be quantified by running PIXE on an original sample and on the residue resulting from acid digestion.     

Experimental study of the Ho(p,n) nuclear reaction for production of the therapeutic radioisotope Er

The 10.3 h half life radionuclide ¹⁶⁵Er, decaying by electron capture to stable ¹⁶⁵Ho, is an excellent candidate for Auger-electron therapy. In the frame of a systematic study of charged particle production routes of ¹⁶⁵Er, the excitation function of the ¹⁶⁵Ho(p,n)¹⁶⁵Er reaction was measured up to 35 MeV by using a stacked foil irradiation technique and X-ray spectroscopy. The measured excitation function shows a significant energy shift when compared to the only experimental dataset measured earlier and an acceptable agreement with the results of different nuclear reaction model codes. The thick target yields calculated from the excitation function at typical energies available at small cyclotrons (E_p = 11 MeV and E_p = 15 MeV) are 41 MBq/μAh = 11 GBq/C and 75 MBq/μAh = 21 GBq/C, respectively.     

大庆长垣以东地区泉一、二段泥岩盖层封气能力综合评价

为了准确评价盖层毛细管封闭能力 ,综合考虑盖层本身封闭性和宏观发育特征及天然气本身性质对封闭能力的影响 ,给出了假定外力作用下天然气通过泥岩盖层渗滤速度的计算公式及参数确定方法 ,并根据泥岩盖层渗滤速度的大小 ,提出了泥岩盖层封气能力等级划分标准 .采用该方法综合评价了大庆长垣以东地区泉一、二段泥岩盖层封气能力 ,结果表明 :泉一、二段泥岩盖层在安达 -肇洲背斜带具有好的封气能力 ,由此向东北和东南封气能力由好变差     

一类q-变形叠加态光场的压缩特性

构造了一种曲ｑ－变形相干态与ｑ－变形真空态叠加而成的态,研究了它的压缩性质（二阶压缩和高阶压缩）,借助数值计算方法讨论了叠加系数、变形参数对叠加态压缩特性的影响。     

321-Q370q复合板焊接性能试验研究

桥梁结构复杂,构件制作时需大量采用焊接,焊接的方法主要是埋弧自动焊,为了验证321-Q370q复合板能否满足桥梁用钢的焊接要求,对复合板埋弧焊接头进行了一系列性能试验。试验结果表明,焊接接头各项性能均能满足相关标准要求。     

中国人均GDP的时间序列模型的建立与分析

综合运用了判别时间序列平衡性的方法,建立了中国人均GDP的时间序列模型为了消除虚假回归,利用单位根方法检验了时间序列的单整阶数;在判别差分序列的平衡性之后,利用自相关函数图和偏相关函数图判别了时间序列模型的自回归阶数（AR（P）和移动平均阶数MA（q);然后利用TSP软件用OLS法对时间序列模型的回归参数进行了估计与显著性检验,并对通过检验的回归结果进行了分析。     

A changing society and problems of method: a politically committed research type

This essay examines a politically engaged research genre, which follows the biography of the author who founded two journals: one on mathematical models published in English (Quality and Quantity) and one on politically committed social and economic research published in Italian (Inchiesta). The research considered focuses on Italy in the 1950s, the research by Lazarsfeld in Vienna in the 1920s and in the United States in the 1950s and 1960s, and post-1968 politically committed research in Italy. The analysis of such politically committed types of research (all very different from one another in terms of the interpretative model of reality, the methods used and the relations with the tendering party and the people observed) allows one to understand how this kind of research can be performed with very different methods—all of which do, however, seek to modify reality on the grounds of the research results. The metaphor of the crystal and the flame presented by Italo Calvino in order to q8v9e343y7v/xxlarge8220.gif" alt="ldquo" align="MIDDLE" BORDER="0">classify facts and ideas and styles and feelingsq8v9e343y7v/xxlarge8221.gif" alt="rdquo" align="MIDDLE" BORDER="0"> can also be used to visualise the polarity (and the difficulty/impossibility of contact) that has always been present in sociology between two different tendencies: towards a discipline that offers the most abstract and objective interpretative model of reality possible with the use of mathematical models (the crystal), and, instead, towards a discipline in which an interpretative model of reality is central, one that produces a social change and in which the qualitative and quantitative methods utilised are at the service of this change (the flame). This polarity thus allows us to separate first and foremost all the politically committed research performed by others for different purposes (market research, research to verify some theoretical hypotheses, etc.) but the same polarity also lies within the politically committed research. We can, indeed, identify a type of politically committed research in an area that has, at one extreme, research tending towards the utmost q8v9e343y7v/xxlarge8220.gif" alt="ldquo" align="MIDDLE" BORDER="0">objectivityq8v9e343y7v/xxlarge8221.gif" alt="rdquo" align="MIDDLE" BORDER="0"> and q8v9e343y7v/xxlarge8220.gif" alt="ldquo" align="MIDDLE" BORDER="0">scientific qualityq8v9e343y7v/xxlarge8221.gif" alt="rdquo" align="MIDDLE" BORDER="0"> of the results and where the co-ordinators try to have all the information on the subjects maintaining the greatest possible distance (the subjects must not know they are being observed); at the other extreme, there is a type of research in which the coordinator completely involves the subjects in the gathering of information that will serve to realise a piece of research whose political aims are explicitly shared. For the identification of a sufficiently articulated typology it has been important to consider five dimensions of politically committed research: (a) the characteristics of the research coordinator (his/her belonging to the type and the academic/non-academic professional status) and his/her interpretative model of reality (b) some general characteristics of the research (the tender and funding, the topic choice, the aims, the contributions to the sociological theory, the duration); (c) the research coordinatorq8v9e343y7v/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0">s relations with the political actors (the intensity of the relations, the political use of the research); (d) the relations of the research co-ordinator with the research subjects; (e) the methodological choices (the basic strategies, the methods used, the use of mathematical procedures). The research that exemplifies this typology is all politically committed to the left and was realised in different times and contexts. I start by considering a kind of politically engaged research (co-research) that appeared in Italy in the 1950s; I then analyse two types of politically engaged research realised in Austria at the end of the 1920s and one in the United States in the 1950s; there then follow two kinds of research realised in the 1960s and 1970s in the United States and a further two kinds realised in Italy in the 1970s and early 1980s. In order to have other kinds of research please refer to the two Journals of which I am the editor: one is an English language journal of mathematical models (Quality and Quantity, International Journal of Methodology, founded in 1966 and published today by Kluwer of Amsterdam), and a politically engaged review (Inchiesta, founded in 1971 and still published today by Dedalo of Bari).     

一种高性能三电平PWM整流器控制技术的研究

提出将直流电机的双闭环控制方法应用于三电平PWM整流器上,建立了电压电流解耦框图,对解耦后的d,q轴电流进行了独立的PI控制。仿真和实验研究发现,该整流器不但能够有效地抑制谐波,电磁干扰(EMI)较小,而且可以实现单位功率因数运行,具有良好的动态性能和稳态性能,且自调节能力较强,鲁棒性很好。     

基于转子位置传感器的同步发电机■波形实时生成方法

同步发电机空载电势■的有关参数对电力系统的运行与控制都是非常重要的,但是,目前现场的监控装置想要得到■的相关参数仍然存在困难。文中提出一种基于转子位置传感器的同步发电机■波形的实时生成方法,依据该方法开发的装置能够输出频率和相位都与空载电势■一致而幅值恒定的正弦电压信号,从而使得现场的监控装置能够像测量发电机机端电压那样方便地测量空载电势■的有关参数。详细地介绍了这种方法的工作原理和实现技术。     

ACBD3 Bioinformatic Analysis and Protein Expression in Breast Cancer Cells

ACBD3 overexpression has previously been found to correlate with worse prognosis for breast cancer patients and, as an incredibly diverse protein in both function and cellular localisation, ACBD3 may have a larger role in breast cancer than previously thought. This study further investigated ACBD3′s role in breast cancer. Bioinformatic databases were queried to characterise ACBD3 expression and mutation in breast cancer and to investigate how overexpression affects breast cancer patient outcomes. Immunohistochemistry was carried out to examine ACBD3 location within cells and tissue structures. ACBD3 was more highly expressed in breast cancer than in any other cancer or matched normal tissue, and expression over the median level resulted in reduced relapse-free, overall, and distant metastasis-free survival for breast cancer patients as a whole, with some differences observed between subtypes. IHC analysis found that ACBD3 levels varied based on hormone receptor status, indicating that ACBD3 could be a candidate biomarker for poor patient prognosis in breast cancer and may possibly be a biomarker for ER signal reprogramming of precancerous breast tissue.