982 resultados para Argon-36
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针对①中能反应中同位旋自由度是否达到平衡,②同位旋自由度对几中不同方法测量的核温度是否有影响 这两个基本问题,设计了用30和35MeV/u ~(36,40)Ar轰击~(112,124)Sn反应的实验方案。得到如下结果:对于前角5°处的耗散弹核碎裂产物,丰中子同位素与稳定核的产额比随产物出射动能的增加而减小,而丰质子子同位素与稳定核的产额比随动能的增加而增加,呈现明显的剪刀差分布特性。随耗散时间的增大,产物的平均中质比逐渐由弹核的平均中质比向系统的平均中质比过渡。这个结果说明在该反应中,同位旋自由度没有达到完全平衡。而对于20°处的DIC产物,上述剪刀差分布特性变得更不明显,这是同位旋自由度由非平衡向平衡过渡的表现。后角轻粒子的能谱分析表明,初始热核的同位旋会影响斜率核温度的提取,由于丰中子轻粒子~6He在~(40)Ar + ~(112)Sn系统中的蒸发被抑制,相比~(40)Ar + ~(112)Sn而言,其蒸发比较容易发生在衰变链早期,因此提取的温度偏高,同样,丰质子轻粒子~3He的温度在~(40)Ar + ~(112)Sn中略高。但中后角的同位素产额分析表明,反应系统的同位旋对双同位素比核温度几乎没有影响。核温度作为热核的热力学量,是独立于测量方法的,这种不同的方法得出的差异主要来源于同位旋对衰变机制的影响。作为一个尝试,将中高能反应中的熵的提取推广到这个能区,发现两个系统的熵几乎一致。在量子统计模型框架下,考察核温度与熵的关系发现,~(40)Ar + ~(112)Sn反应的挤出时刻密度略高于~(40)Ar + ~(112)Sn。
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本文描述了一个能在中解(10-100Mev/u)重离子核反应测量中鉴别轻粒子,测量粒子多重性,并能给出轻粒子能量和位置信息的大立体角(θ: 5°-20°φ: 0°-360°)的36单元塑料闪烁体陈列探测器的制作与调试,初步调试结果表明该探测器对轻粒子(p、α等)有较好的分辨。同时对国际上几种规模较大的先进的多单元大立体角粒子探测系统作了比较全面的介绍
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Ultrathin multilayer films of the wheel-shaped molybdenum polyoxometalate cluster (Mo-36)(n) and poly(allylamine hydrochloride) (PAH) have been prepared by the layer-by-layer (LbL) self-assembly method. The ((Mo-36)(n)/PAH)(m) multilayer films have been characterized by Xray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). UV-VIS measurements reveal regular film growth with each (Mo-36)(n) adsorption. The electrochemical behavior of the film at room temperature was investigated.
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Pyrolysis of hyperbranched poly[1,1'-ferrocenylene(methyl)silyne] (5) yields mesoporous, conductive, and magnetic ceramics (6). Sintering at high temperatures (1000-1200 degrees C) under nitrogen and argon converts 5 to 6N and 6A, respectively, in similar to 48-62% yields. The ceramization yields of 5 are higher than that (similar to 36%) of its linear counterpart poly[1,1'-ferrocenylene(dimethyl)silylene] (1), revealing that the hyperbranched polymer is superior to the linear one as a ceramic precursor. The ceramic products 6 are characterized by SEM, XPS, EDX, XRD, and SQUID. It is found that the ceramics are electrically conductive and possess a mesoporous architecture constructed of tortuously interconnected nanoclusters. The iron contents of 6 estimated by EDX are 36-43%, much higher than that (11%) of the ceramic 2 prepared from the linear precursor 1. The nanocrystals in 6N are mainly alpha-Fe2O3 whereas those in 6A are mainly Fe3Si. When magnetized by an external field at room temperature, 6A exhibits a high-saturation magnetization (M-s similar to 49 emu/g) and near-zero remanence and coercivity; that is, 6A is an excellent soft ferromagnetic material with an extremely low hysteresis loss.
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beta, beta-1, 3-Piopylenedithio-alpha, beta-unsaturated arylketones 2 via chemoselective 1,2-addition with allyl or benzyl Grignard reagents afforded the corresponding carbinols 3 and 4. Catalysed by silica gel, the carbinols 3 and 4 were converted to the beta,gamma-unsaturated arylketones 5, 6. The mechanism and reaction condition were discussed.
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Helium, rieon and argon isotope compositions of fluid inclusions have been measured in hydrothermal sulfide samples from the TAG hydrothermal field at the Mid-Atlantic Ridge. Fluid-inclusion He-3/He-4 ratios are 2.2-13.3 times the air value (Ra), and with a mean of 7.2 Ra. Comparison with the local vent fluids (He-3/He-4=7.5-8.2 Ra) and mid-ocean ridge basalt values (He-3/He-4=6-11 Ra) shows that the variation range of He-3/He-4 ratios from sulfide-hosted fluid inclusions is significantly large. Values for Ne-20/Ne-22 are from 10.2 to 11.4, which are significantly higher than the atmospheric ratio (9.8). And fluid-inclusion Ar-40/Ar-36 ratios range from 287 to 359, which are close to the atmospheric values (295.5). These results indicate that the noble gases of fluid inclusions in hydrothermal sulfides are a mixture of mantle- and seawater-derived noble gases; the partial mantle-derived components of trapped hydrothermal fluids may be from the lower mantle; the helium of fluid inclusions is mainly from upper mantle; and the Ne and Ar components are mainly from seawater.
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Practice Links is a free e-publication for practitioners working in Irish social services, voluntary and nongovernmental sectors. Practice Links was created to enable practitioners to keep up-to-date with new publications, electronic resources and conference opportunities. Issue 36 features articles on equine assisted personal development, the National Child Care Information System and a report on Fieldwork Training for Social Workers
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p.167-171
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This paper investigated whether the SF-12 could replace the SF-36 in the measurement of health status among ischaemic heart disease patients. The SF-36 and SF-12 were administered to 105 cardiac patients. The SF-36 summary scores were strongly correlated and similar to the SF-12 summary scores. Also, the SF-12 scores were as powerful as the SF-36 summary scores in discriminating between subgroups of patients categorized according to their self-reported health status or angina classification. It is suggested that when there is a need to collect routine information about cardiac patients' general physical and mental health, the SF-12 is preferable to the SF-36 because of its brevity and acceptability to patients.