35 resultados para HALO


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We measured the total reaction cross sections of N-12 in Si at 36.2 MeV/u. using Radioactive Ion Beam Line in Lanzhou (RIBLL) with a new method. The reaction target was installed at the intermediate focusing point T1 at RIBLL. This scheme allows us to identify particles before and after the reaction target unambiguously. The total reaction cross section (1760 +/- 78mb) of N-12 in Si is obtained. Assuming that N-12 consists of a core C-11 plus one halo proton, the excitation function of N-12 on the Si and C targets is calculated with the Glauber model and the Fermi-Fermi density distributions. It can fit the experimental data very well. A large diffusion of the protons density distribution supports the halo structure for N-12.

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本论文主要包括两部分内容,一部分是关于中能重离子碰撞中的同位旋效应和同位旋非对称核物质状态方程,第二部分是改进的Glauber理论和晕核核结构的研究.利用同位旋相关的量子分子动力学模型(IQ\MD)系统而仔细的研究了同位旋相关的平均场和介质中核子核子碰撞截面对中能重离子碰撞中碎裂和耗散的同位旋效应.研究在国际上首次发现原子核阻止,中等质量碎片多重性和质子(中子)发射数都敏感的依赖于介质中核子一核子碰撞截面的同位旋效应,而对于同位旋相关的平均场(又寸称势)很不灵敏.故这些物理量可以作为提取相对高能范围缺中子系统同位旋相关介质中核子一核子碰撞故面的灵敏探针.另一方而,与前三种物理观测量相反,研究发现在相对较低能区前平衡核子发射中质比和同位旋分馏强度灵敏的依赖于对称势,而对于同位旋相关介质中核子一核子碰撞截面很不灵敏,可以用来提取同位旋相关平均场的知识.在此基础上分别研究了动量相关作用,核介质效应和库仑作用分别对提取上述知识动力学过程的机理和影响,研究发现这三种动力学因素对中能重离子碰撞过程中的同位旋效应有重要影响.例如研究发现核子一核子碰撞的介质效应明显增加了中等质量碎片多重性和核子发射数对于核子一核子碰撞截面的灵敏性.库仑作用降低了同位旋分馏和原子核阻止.但不影响它们分别对平均场和两体碰撞同位旋效应的灵敏性.动量相关作用明显增加了各种物理观测量对于平均场或两体碰撞截面同位旋效应的灵敏性.以上的研究结果对建立同位旋非对称核物质状态方程具有重要的参考价值和学术意义.在考虑量子修正、库仑修正、核子一核子碰撞同位旋效应和假定有效原子核密度分布后将仅适用于计算高能核子对原子核反应总截面的Glouber理论推广到能适用于中低能情况下核一核反应的Glaube理论.研究发现在应用推广的Glauber理论计算中、低能核一核反应截面时,量子修正是重要的.利用修正了的Glauber理论,系统计算了从低能到较高能大量稳定线附近30个核一核反应总截面,在没有可调参数的情况下,都与实验结果较好地符合.在计算晕核与稳定核反应总截面时,发现对于"Be,"Be和" Li等入射晕核,必须考虑它们的晕核结构才能得到与实验符合的反应截面,并可依据反应总截面来提取晕核的密度分布和均方半径等信息,以此来判定晕核的存在。

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A series of liquid crystalline copolyethers has been synthesized from 1-(4-hydroxy-4'-biphenyl)-2-(4-hydroxyphenyl)propane and different alpha,omega-dibromoalkanes [coTPP(n/m)]. In this report, coTPPs having n = 5, 7, 9, 11 and m = 12 are studied, which represent copolyethers having both varying odd number and a fixed even number of methylene units. The compositions were fixed at an equal molar ratio (50/50). These coTPPs(nlm) show multiple phase transitions during cooling and heating in differential scanning calorimetry experiments. The undercooling dependence of these transitions is found to be small, indicating that these transitions are close to equilibrium, Although the coTPPs possess a high-temperature nematic (N) phase, the periodicity order along the chain direction is increasingly disturbed when the length of the odd-numbered methylene units decreases from n 11 to 5. in the coTPPs(5/12, 7/12, and 9/12), wide-angle X-ray diffraction experiments at different temperatures show that, shortly after the N phase formation during cooling, the lateral molecular packing improves toward a hexagonal lattice, as evidenced by a gradual narrowing of the scattering halo. This process represents the possible existence of an exotic N phase, which serves as a precursor to the columnar (Phi(H)) phase. A further decrease in temperature leads to a (PH phase having a long-range ordered, two-dimensional hexagonal lattice. In coTPP(11/12), the phase structures are categorized as highly ordered and tilted, smectic and smectic crystal phases, similar to homoTPPs, such as the smectic F (S-F) and smectic crystal G (SCG) phases. An interesting observation is found for coTPP(9/12), wherein a structural change from the high-temperature Phi(H) phase to the low-temperature S-F phase occurs. It can be proven that, upon heating, the well-defined layer structure disappears and the lateral packing remains hexagonal. The overall structural differences in this series of coTPPs between those of the columnar and highly ordered smectic phases are related to the disorders introduced into the layer structure by the dissimilarity of the methylene unit lengths in the comonomers.

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With the progress of prospecting, the need for the discovery of blind ore deposits become more and more urgent. To study and find out the method and technology for the discovery of blind and buried ores is now a priority task. New geochemical methods are key technology to discover blind ores. Information of mobile components related to blind ores were extracted using this new methods. These methods were tested and applied based on element' s mobile components migrating and enriched in geophysical-geochemical process. Several kinds of partial extraction techniques have tested based on element' s occurrence in hypergenic zone. Middle-large scale geochemical methods for exploration in forest and swamp have been tested. A serious of methods were tested and applied effetely about evaluation of regional geochemical anomaly, 1:25000 bedrock or soil geochemical methods sampling based on the net in dendritic water system instead of the normal net. 1. Element related with ores can be mobiled to migrate upwards and be absorpted by surface soil. These abnomal components can be concentrated by natural or artificial methods. These trace metalic ions partially exist in dissovlvable ion forms of active state, and partially have been absorbed by Fe-Mn oxide, soil and organic matter in the soil so that a series of reaction such as complex reaction have take place. Employing various partial extraction techniques, metallic ions related with the phase of the blind ores can be extracted, such as the technique of organic complex extraction, Fe-Mn oxide extraction and the extraction technique of metallic ions of various absorption phases. 2.1:200000 regional geochemical evaluation anomaly methods: Advantageous ore-forming areas were selected firstly. Center, concentration, morphological feature, belt of anomaly were choosed then. Geological and geochemical anomalies were combined. And geological and geochemical background information were restrained. Xilekuduke area in Fuyun sheet , Zhaheba area in Qiakuerte sheet, the west-north part in Ertai sheet and Hongshanzui anomaly in Daqiao sheet were selected as target areas, in Alertai, in the north of Xinjiang. in Xilekuduke area, 1:25000 soil geochemical methods sampling based on the net in dendritic water system was carried out. Cu anomaly and copper mineralization were determined in the center area. Au , Cu anomalies and high polarization anomaly were determined in the south part. Prospecting by primary halo and organic complex extraction were used to prognosis blind ore in widely rang outcrop of bedrock. 1:25000 bedrock or soil geochemical methods sampling based on the net in dendritic water system were used in transported overburden outside of mining area. Shallow seismic method and primary halo found a new blind orebody in mining area. A mineralization site was fou and outside of Puziwan gold mine, in the north of Shanxi province. Developing middle-large scale geochemical exploration method is a key technique based 1:200000 regional geochemical exploration. Some conditions were tested as Sampling density , distribution sites of sample, grain size of sample and occurrence of element for exploration. 1:50000 exploration method was advanced to sample clast sediment supplement clast sediment in valley. 1:25000 bedrock or soil geochemical methods sampling based on the net in dendritic water system was applied to sample residual material in A or C horizon. 1:2000 primary or soil halo methods used to check anomalies and determine mineralization. Daliang gold mineralization in the northern Moerdaoga was found appling these methods. Thermomagnetic method was tested in miniqi copper-polymetallic ore. Process methods such as grain size of sample, heated temperature, magnetic separating technique were tested. A suite of Thermomagnetic geochemical method was formed. This method was applied in Xiangshan Cu~Ni deposit which is cover by clast or Gobi in the eastern Xinjiang. Element's content and contrast of anomaly with Thermomagnetic geochemical method were higher than soil anomaly. Susceptibility after samples were heated could be as a assessment conference for anomaly. In some sectors thermo-magnetic Cu, Ni, Ti anomalious were found outside deposits area. There were strong anomal ies response up ore tested by several kind of partial extraction methods include Thermomagnetic, enzyme leach and other partial extractions in Kalatongke Cu-Ni deposit in hungriness area in the northern of Xinjiang. Element's anomalies of meobile were mainly in Fe-Mn oxide and salt. A Copper mineralization site in Xilekuduke anomaly area had been determined. A blind ore was foung by shallow seismic and geochemical method and a mineralization site was found outside this mining area in Puziwan gold deposit in shanxi province. A Gold mineralization site was found by 1:50000 geochemical exploration in Daliang, Inner Mongolia.

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Two kinds of rating bias ——halo effect and ego-centric effect were analyzed in multitrait-multirater matrix by this research. To get the multitrait-multirater matrix, ten college students watched the video-tapes of football matches and rated the performance of the players on several traits. After the interviewing of 41 football fans, the performance traits of four different positions in a football team were obtained using critical incident technique. The results indicate: comparing the heterotrait-monorater triangless, some rater's rating showed halo effect obviously; comparing the monotrait-heterorater diagonals, ego-centric effect can be shown in some extent on different traits. There were less interrater reliability on the rating of some ambiguous traits. The conclusion can be used on rater training. We can give the raters feedback about their rating bias by analyzing the multitrait-multirater matrix. The results are also helpful for rater training.