共查询到20条相似文献,搜索用时 15 毫秒
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David J. Foulis 《Foundations of Physics》2007,37(10):1421-1446
We show how effect algebras arise in physics and how they can be used to tie together the observables, states and symmetries
employed in the study of physical systems. We introduce and study the unifying notion of an effect-observable-state-symmetry-system
(EOSS-system) and give both classical and quantum-mechanical examples of EOSS-systems. 相似文献
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ICP-AES法同时测定螺旋藻中Ca、Mg、P、Fe、Cu、Mn、Zn 总被引:9,自引:2,他引:7
本文研究了干法灰化,盐酸溶解盐类,ICP-AES技术同时测定螺旋藻中Ca、mg、P、Fe、Cu、Mn、Zn的方法,进行了共存离子干扰和谱线干扰试验,对Cu、Mn、Zn进行了AAS法测定对比。方法的相对标准偏差为1.39%-5.02%,标准回收率为95.6%-104.8%。方法快速、准确、可靠。 相似文献
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Wallace Rubin 《Journal of voice》1988,1(4):378-385
Allergic, dietary, chemical, biochemical, stress, and hormonal abnormalities have long been recognized as important factors in both abnormalities of the voice and in the general health of the professional vocalist. In recent years objective methods have become available to evaluate and treat allergic, dietary, and chemical abnormalities and to better understand the effects of stress and hormonal variations. Assessment of allergic disease is efficient and cost effective through the use of in vitro testing techniques combined with skin end point titration. This provides highly specific and objective results and leads to accurate planning of desensitization treatment. This form of treatment can be especially beneficial in the prevention of recurrent laryngitis. An accurate nutritional history provides evidence of food sensitivities that can lead to cyclical allergic-like vocal symptoms that can be prevented with the use of elimination diets and the judicious use of desensitization therapy. An adequate knowledge of the potential effects of chemical sensitivities will assist the patient in the avoidance of provocative chemical exposures. An in depth evaluation of biochemical abnormalities and a specific assessment of the nutritional status must be considered to evaluate the underlying causes of long-standing general health problems that can affect the voice. Likewise, hormonal variations are not only important in their direct effects on the vocal mechanism but in their cyclical effects on the patient's basic biochemical balance. Lastly, stress, which has long been related to problems in professional performance, is only now being fully studied to determine its actual biologic influences and these must be related to the causes of voice disturbances. Understanding all these influences and planning a rational and efficient evaluation of these potential problem areas are imperative in the complete care of the patient with voice abnormalities. 相似文献
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Charles A. Kingsbury Jon Weinhold Jeremy Winter 《Journal of Physical Organic Chemistry》2007,20(3):161-166
Three reactions were studied in the diastereomers of 1‐(benzenesulfonyl)‐2‐nitro‐1‐phenylpropane ( 1A and 1B ) and briefly in related compounds: elimination of the benzenesulfonyl group, epimerization of one diastereomer to the other, and deuterium/hydrogen exchange at the methine group next to nitro in starting material. The two diastereomers showed quite different reactivity. The high melting diasteromer showed rapid elimination and some exchange. The low melting diastereomer (at approximately a half‐life) showed extensive epimerization, and elimination to the alkene, but little exchange. There is little effect of aromatic substituents on reaction course. The situation is complicated by re‐addition of benzenesulfinate to the alkene. The addition reaction was similar to elimination in agreement with the Principle of Microscopic Reversibility expectations. An electron transfer mechanism for addition is calculated to be comparatively favorable. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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Z.-Z. Zhang S.-G. Zhou T. Zou 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,56(3):259-271
In this paper, firstly, we study analytically the topological
features of a family of hierarchical lattices (HLs) from the view
point of complex networks. We derive some basic properties of HLs
controlled by a parameter q: scale-free degree distribution with
exponent γ=2+ln 2/(ln q), null clustering
coefficient, power-law behavior of grid coefficient, exponential
growth of average path length (non-small-world), fractal scaling
with dimension dB=ln (2q)/(ln 2), and disassortativity.
Our results show that scale-free networks are not always
small-world, and support the conjecture that self-similar scale-free
networks are not assortative. Secondly, we define a deterministic
family of graphs called small-world hierarchical lattices (SWHLs).
Our construction preserves the structure of hierarchical lattices,
including its degree distribution, fractal architecture, clustering
coefficient, while the small-world phenomenon arises. Finally, the
dynamical processes of intentional attacks and collective
synchronization are studied and the comparisons between HLs and
Barabási-Albert (BA) networks as well as SWHLs are shown. We
find that the self-similar property of HLs and SWHLs significantly
increases the robustness of such networks against targeted damage on
hubs, as compared to the very vulnerable non fractal BA networks,
and that HLs have poorer synchronizability than their counterparts
SWHLs and BA networks. We show that degree distribution of
scale-free networks does not suffice to characterize their
synchronizability, and that networks with smaller average path
length are not always easier to synchronize. 相似文献
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电感耦合等离子体-原子发射光谱法直接测定RA合金中Al、Cd、Cu、Fe、Pb、Mn和Si等元素含量。优选了适宜的仪器测定参数和分析谱线。方法简便快速。回收率在97%—103%之间,相对标准偏差(RSD)<5%。 相似文献
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原子吸收光谱法测定桃叶中K,Mg,Sr,Fe,Cu,Mn和Zn等元素 总被引:2,自引:0,他引:2
本文采用桃叶作标准样品,讨论了湿法消化法与炭化-灰化法两种样品处理方法对测定结果的影响及方法操作效果比较,并进一步讨论了温度对炭化-灰化法的影响情况。由此建立起该法的适宜条件。在此条件下,用原子吸收光谱法测定桃叶及冷杉树枯枝、叶中多种元素。其精密度和准确度均能满足测定要求。 相似文献
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ICP-AES法测定金属硅中的Al、B、Ba、Ca、Cr、Cu、 Fe、Mg、Mn、Ni、Sr、Ti、V和Zn杂质元素 总被引:13,自引:0,他引:13
本文提供了一种测定金属硅中B,Fe,Al,Ca,Mn等14个杂质元素的ICP-AES方法,在样品处理过程中,加入适量体积的甘露醇能够抑制B的挥发。用本方法测定了一个国家地球化学标准样(GSR-4),结果令人满意。 相似文献
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纯硒中杂质元素的ICP-AES测定 总被引:1,自引:0,他引:1
电感耦合等离子体-原子发射光谱同时测定纯硒中的碲、铅、铋、锑、铜、铁、镍、铝、锡、砷和硼12种元素的含量,优化出各元素的分析波长和分析条件;用基体匹配补偿基体效应,方法简单,快速可靠,样品回收率为94%-107%. 相似文献
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藻类植物中钙、镁、铁、锰、铜和锌含量分析 总被引:15,自引:2,他引:13
本文采用火焰原子吸收光谱法测定了七种藻类植物中钙 ,镁 ,铁 ,锰 ,铜 ,锌六种元素的含量。结果表明 ,藻类植物中含有较丰富的钙 ,镁 ,铁 ,锰 ,锌元素 ,其含量由大到小顺序为Ca >Mg >Fe >Zn >Mn >Cu ,尤以钙的含量最为丰富 ,铜含量较少。本实验结果为探讨藻类植物作为资源开发利用提供了有用数据。 相似文献
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ICP—AES法直接测定锡锭中的As,A1,Bi,Cd,Cu,Fe,Pb,Se,Sb,Zn 总被引:4,自引:0,他引:4
以电荷耦合器件为检测器的全谱直读等离子体光谱仪直接测定锡锭中As、A1、Bi、Cd、Cu、Fed、Pb、Se、Sb、Zn十种杂质元素的含量。该方法简便、快速且具有比化学法更低的检出限,加标回收试验结果不明,回收率为92%-105%,RSD均小于1.5%。 相似文献
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ICP-AES法测定铝合金中Fe、Si、Mo、Zr、Ti、Y的研究 总被引:13,自引:3,他引:10
本文采用ICP-AES法测定了铝合金中Fe、Si、Mo、Zr、Ti、Y,并对样品的溶解方法、共存元素间的光谱干扰、内标元素的选择等进行了研究,建立的分析方法简便快速,有较好的精密度和准确度。 相似文献
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M. Carmeli 《International Journal of Theoretical Physics》1997,36(3):757-770
In the limit of negligible gravity, a transformation that relates physical quantities at different cosmic times, similar to
the Lorentz transformation which relates measurments at different velocities, is derived. 相似文献