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1.
Directed flow and elliptic flow of final state particles in high-energy nucleus-nucleus collisions in the EMU01 experiment have been studied.The dependences of directed flow and elliptic flow on incident energy and impact centrality of outgoing particles are presented.The results exhibit strong dependence of flow on centrality and energy.We also suggest a more reliable way to determine the event plane resolution here.  相似文献   

2.
阐述了9,11Be+209Bi近垒熔合反应研究的意义,给出实验结果并讨论弹核破裂对近垒熔合反应截面的影响. The purpose and importance of the study of 9,11Be+209Bi near barrier fusion were reviewed. The breakup effects of the halo nuclei on fusion were discussed and compared with the experimental results of 9,11Be+209Bi systems.  相似文献   

3.
简要评述超核物理学近几年的发展,包括常规超核和非常规超核两个方面.对于包含通常超子的常规超核,重点介绍近来在日本KEK完成的一批超核实验及其理论分析.对其中关于超子杂质效应和超子平均自由路程等实验测量结果进行了理论分析,得到一些有意义的结果.并对奇异数为S=-2的Ξ超核的结构和性质进行了若干研究.对于包含C夸克或B夸克的其他味超核,以及可能的包含pentaquark的θ+超核也做了适当的介绍. Progress and recent status of experimental and theoretical investigations on hypernuclear physics are briefly reviewed, including conventional hypernuclear physics and unconventional hypernuclear physics. We introduce the recent progress of hypernuclear experiments in KEK, Japan and the studies of fine structure in γ-ray spectroscopy of Λ hypernuclei. The spin-flip transition between the ground-state spin doublet of light hypernuclei has been observed and the transition energy provides important..  相似文献   

4.
核电池材料及核电池的应用   总被引:1,自引:0,他引:1  
核电池具有体积小、寿命长、不受外界环境影响等优点,因而在航空航天、深海、极地、心脏起搏器、微型电机等领域得到广泛地应用。核电池的发展与所用材料的发展互相促进。从同位素放射源、电能转换、密封保护的角度介绍了核电池所用材料的发展和最新研究进展,同时也介绍了核电池现有和潜在的应用领域。Nuclear battery has lots of advantages such as small volume, longevity, environal stability and so on, therefore, it was widely used in aerospace, deep-sea , polar region, heart pacemaker, micro-electromotor and other fields etc. The application of nuclear battery and the development of its materials promote each other. In this paper the development and the latest research progress of nuclear battery materials has been introduced from the view of radioisotope, electric energy conversion and encapsulation. And the current and potential applications of the nuclear battery are also summarized.  相似文献   

5.
爆发性核合成与核结构   总被引:2,自引:0,他引:2  
讨论了天体物理环境中爆发性核合成及其与核结构的紧密关系.用反射不对称壳模型计算了远离稳定线丰中子核148Ba的低能八极转动带,结果与实验很好符合.展示了其应用于不稳定核低能态计算的有效性 ,以及在核天体物理研究中的应用前景.The explosive nucleosynthesis in the astrophysical environment and its close link to nuclear structure are discussed. The low lying octupole bands for neutron rich nucleus 148 Ba far from the stability line have been calculated by the reflection asymmetric shell model and the results are in good agreement with the experimental data, presenting the capability of the model for calculations of the low lying states of unstable nuclei as well as the foreground of application in nuclear astrophysics.  相似文献   

6.
简单回顾了超重核的理论研究现状,讨论了形变对长寿命重核α衰变半衰期的影响。分析了相对论平均场模型的有效范围。强调了α衰变、结团放射性和自发裂变中应保持宇称守恒。提出了一些新观点。Status of theoretical studies on superheavy nuclei is simply reviewed.We investigate the influence of nuclear deformation on half lives of α decay forlong lifetime nuclei beyond 208Pb. The range of the validity of relativistic mean field model is analyzed and discussed. The conservation of parity in α decay, cluster radioactivity, and spontaneous fission of nuclei is stressed. New views on the properties of superheavy nuclei are presented.  相似文献   

7.
本文简要评述了中能重离子碰撞中可能存在的奇异密度分布形状──气泡核和环形核的形成,并论述了实验观测方面的可能特征. Possible existence of the exotic density shapes-the formation of nuclear bubbles and rings-in the domain of intermediate energy heavy ion collisions have been briefly reviewed. Some experimental consequences were dicussed.  相似文献   

8.
核天体物理是研究微观世界的核物理与研究宏观世界的天体物理融合形成的交叉学科,其主要研究目标是:宇宙中各种化学元素核合成的过程、时间、物理环境、天体场所及丰度分布;核反应(包括带电粒子、中子、光子及中微子引起的反应、β衰变及电子俘获)如何控制恒星的演化过程和结局。近十多年来获得的大量实验和理论研究使核天体物理研究进入了一个蓬勃发展的新阶段。文章总结了以兰州重离子加速器、北京串列加速器和国家天文台为基础,结合国际合作,在核天体物理研究领域对直接测量、间接测量、衰变测量、质量测量、理论计算、网络计算、天文观测等关键科学问题进行的研究进展。也展望了核天体物理的关键科学问题,这些关键问题包括:(1)在地面实验室、尤其是地下实验室开展天体物理能区重要热核反应截面的直接测量;(2)高能区带电粒子反应截面向天体物理能区的合理外推;(3)恒星平稳核燃烧阶段和爆发性天体事件中关键核反应截面的间接测量;(4)爆发性天体事件中所涉及的大量远离稳定线核素的质量、衰变特性和共振态性质的研究;(5)建立并不断完善核天体物理数据库,发展网络模拟程序,系统研究元素核合成的天体场所、丰度分布;(6)宇宙中铁以上元素的来源之谜。Nuclear astrophysics is an interdisciplinary research field. It composes of nuclear physics, which studies micro phenomena, and astrophysics which studies macroscopic phenomena in our world. The main research goals of nuclear astrophysics are:(1) how, when and where chemical elements are synthesized and what is their final abundance distribution in the universe; (2) how nuclear processes (reactions induced by charged particles, neutrons, photons and neutrinos, beta decays and electron capture processes) determine the evolution and the ultimate fate of stars. At present, nuclear astrophysics has been developed into a new prosperous stage with a huge number of experimental and theoretical progresses. This paper summarized the current progress of nuclear astrophysics in China, in the subfiels of direct and indirect measurement of key reactions, measurement of mass and decay, as well as the theoretical calculation and network simulation. In present paper, the prospects to solve the key scientific nuclear astrophysics problems are represented. These key problems include (1) direct measurement of important reactions at astrophysical energies in the laboratory on the earth surface and in the underground laboratory; (2)extrapolation of cross sections at higher energies for the reactions induced by charged particles; (3) indirect measurement of key reactions in the hydrostatic and explosive nuclear processes; (4) study of the mass, the properties of decay and resonant states for the nuclides far from the stability line in explosive astrophysical events; (5) establish and improve the database for nuclear astrophysics, and develop network simulation codes, and systematically study astrophysical sites and abundance distribution of nucleosynthesis; (6) origin of the elements heavier than iron in the universe.  相似文献   

9.
超重核研究实验方法的历史和现状简介   总被引:3,自引:4,他引:3  
简单介绍了超重核合成的历史,详细讨论了目前超重核合成最成功的技术路线,包括产生方法、分离手段以及探测技术,并就各种技术的优缺点进行了比较.探讨了目前超重核研究所面临的困难以及介绍了国际上几个主要相关实验室的研究动态,并对超重核研究的发展趋势做了简单展望. The history of the synthesis of the transuranium nuclei is briefly introduced. The most successful techniques currently used for synthesizing super heavy nuclei are surveyed and discussed in detail. The drawbacks and the problems for reaching the stability island of super heavy nuclei with the techniques currently used are discussed. The present status and perspectives of the super heavy nuclei research at different laboratories are also introduced. Finally, a brief prospect on the trends...  相似文献   

10.
核固体物理的研究给核物理学家为解决物理学基本问题作出新贡献提供了许多的良机.本文概要叙述理论研究背景及用核方法研究凝聚态物质微结构的一些新结果,报道用核方法研究材料组份,讨论辐照条件下固体的结构和行为. The study of nuclear solid-state physics provides many new opportunities for nuclear physicists to contribute to the solution of some of the most of the fundamental questions in physics. This paper gives a brief survey of theoretical background and some new results on the microstructure of condensed matter obtained by nuclear methods.The elemental composition of the materials with nuclear methods are presented. The structure and behaviour of the solids under irradiation is discussed.  相似文献   

11.
A new technique of Mueller-matrix mapping of the birefringent structure of biological preparations of human organs tissues is suggested. The algorithms of reconstruction of average values and magnitude of fluctuations of the phase (birefringence) and amplitude (dichroism) of optically anisotropic structure of myocardium and connective tissue component of the vaginal wall histological section are proposed. The magnitudes and ranges of changes in the statistical moments of the 1st-4th order that characterize the distribution of average values and magnitude of fluctuations of birefringence and dichroism of the myocardium and connective tissue of the vaginal tissues histological sections were determined. Joint studies of distributions of the characteristics of phase and amplitude of the anisotropy of myocardium and connective tissue component of the vaginal wall tissues of different states were performed. The cases of various necrotic changes in the myocardium and pathological conditions of the vagina wall (prolapse of the genitals) are examined. Balanced accuracy of the method of Mueller-matrix polarization-phase and diffuse tomography of optically anisotropic polycrystalline networks in the differentiation of necrotic and pathological changes in human organs is determined.  相似文献   

12.
Combination of several drugs is often necessary especially during long-term therapy. The competitive binding drugs can cause a decrease in the amount of drug bound to protein and increase the biological active fraction of the drug. The aim of this study is to analyze the interactions of Lomefloxacin (LMF) and Colchicine (COL) with human serum albumin (HSA) and to evaluate the mechanism of simultaneous binding of LMF and COL to protein. Fluorescence analysis was used to estimate the effect of drugs on the protein fluorescence and to define the binding and quenching properties of drugs-HSA complexes. The binding sites for LMF and COL were identified in tertiary structure of HSA with the use of spectrofluorescence analysis. The analysis of fluorescence quenching of HSA in the binary and ternary systems show that LMF does not affect the complex formed between COL and HSA. On the contrary, COL decreases the interaction between LMF and HSA. The results of synchronous fluorescence, resonance light scattering and circular dichroism spectra of binary and ternary systems show that binding of LMF and COL to HSA can induce micro-environmental and conformational changes in HSA. The simultaneous presence of LMF and COL in binding to HSA should be taken into account in the multi-drug therapy, and necessity of using a monitoring therapy owning to the possible increase of the uncontrolled toxic effects. Molecular modeling of the possible binding sites of LMF and COL in binary and ternary systems to HSA confirms the spectroscopic results.  相似文献   

13.
侏罗纪优质煤炭资源为煤制油、制气等清洁高效利用提供了丰富的物质基础,其显微组分以富集惰质组为特征,而镜质组与惰质组大分子结构在很大程度上决定了煤的物理化学性质和工艺性能,进而决定了煤炭资源的综合利用效率及附加值。采集并制备了陕北侏罗纪煤田小保当煤矿和柠条塔煤矿的原煤(XR)、富镜质组煤(XV、NV)和富惰质组煤(XI、NI)样品,利用傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)、固体13C核磁共振谱(13C NMR)等手段,结合煤质分析结果,定量表征了不同显微组分富集物分子结构的差异。研究结果表明:XI和NI煤中芳烃结构芳环取代程度低,主要以3个相邻、4~5个相邻的氢原子形式存在,苯环上氢原子较少被其他官能团取代,同时其结构中芳烃C═C骨架振动明显,脂肪结构中亚甲基伸缩振动强度较低,并且甲基含量略高于富镜煤,C═O基团相对含量略高,表明富惰煤有较多含氧桥键相连的芳香结构,其结构中脂族链、脂环基团脱落、断裂以及芳烃富集,支链相对较少且长度较短,芳碳率、芳香度、芳环缩合程度及成熟度较高。XV和NV煤中表面结构中碳的赋存形态“C—C,C—H”,“C—O”的相对含量高于富惰煤,反映其结构中应含较多的芳环取代的脂肪族侧链,XI和NI煤表面结构中氧的赋存形态以“C—O”为主,“C═O”和“COO—”明显高于富镜煤。XV和XI煤的芳碳率分别为57.91%和66.02%,脂甲基碳分别为10.02%和7.84%,质子化芳碳为非质子化芳碳的两倍,XV煤的羰基和羧基碳相对含量较高,两者桥碳和周碳之比分别为0.25和0.40,芳香核结构平均缩合环数分别为2.68和3.03,平均尺寸分别为0.448和0.676 nm,XI煤结构中芳香核以萘和蒽为主,支链化度Lγ分别为0.22和0.19,表明XV比XI存在较多脂肪侧链、饱和环结构,生烃(油)潜力大。  相似文献   

14.
Mechanism and properties of thermally biological effect of Micro waves   总被引:9,自引:0,他引:9  
水在生命体中是大量存在的,它是维持生命的必要物质.它能促进细胞的繁殖和血液的循环,促进和参与生物化学反应,为生物大分子的功能发挥提供适当条件.由于它是具有一定偶极矩的微观小分子,其转动频率是处在微波范围内,所以我们判定生物体中的液态水能吸收一定频率和强度的微波,并可以将所吸收的微波能量转化为水分子无规运动的热能,使水温升高.我们的实验结果应证了这个机制,从而可导致血液循环,细胞繁殖和一些生化反应的加快和增强DNA,蛋白质和酶的生物活性等生物功能.这就是毫米波的生物热效应的机理和特性.  相似文献   

15.
以地黄饮中两味君药山茱萸肉及肉苁蓉的主要成分马钱苷、松果菊苷的提出量及出膏率为指标,对湿法粉碎提取法与煎煮法的提取效率进行了比较研究。结果显示,湿法粉碎提取法所得马钱苷、松果菊苷的量、出膏量较煎煮明显提高。湿法粉碎提取法提取效率高,方法简便,时间短,可用于地黄饮提取。  相似文献   

16.
Soil has its origin in physical processes of comminution and abrasion of rock masses and in chemical processes of solution and recrystallization of rock minerals. After formation it is transported and distributed by a variety of agencies before subaerial or subaqueous deposition. Generally, soils experience a number of cycles of sedimentation, uplift, erosion and redeposition. Their mechanical behaviour under the stresses imposed by engineering structures varies with the type of soil. Both the deformation and failure of soils are of interest in the design of structures and these properties must be studied by special laboratory tests. The solution of a soil engineering problem therefore involves a field investigation and sampling programme to define the boundaries of the soil involved, laboratory testing of the soil, and analytical or computer calculations to determine the displacements and stresses which will occur in the soil and structure. Problems of particular interest include slope failures, the design of earth dams, retaining walls and piled structures, the displacement and failure of soil under buildings and the determination of soil properties on the surface of the moon and other planets.  相似文献   

17.
Menopausal hot flashes are episodes of flushing, increased heart rate, skin blood flow and skin temperature, and a sensation of heat. The thermoregulatory and cardiovascular concomitants of hot flashes are associated with peaks in the levels of various hormones and neurotransmitters in the peripheral circulation. Although hot flashes affect about 75% of women, and are the primary reason that women at menopause seek medical attention, the mechanism of hot flashes is still not understood. Hot flashes vary in frequency and intensity both within and between individuals, and have been thought of as occurring randomly. Yet, some women report that their hot flashes are worse at a particular time of day or year. Initial examination of subjects' recordings of their hot flashes showed diurnal patterns of hot flash occurrence. There also seems to be a diurnal rhythm of hot flash intensity. Continuous physiological monitoring of hot flashes is facilitating the analysis of these patterns, which is revealing circadian and ultradian periodicities. The occurrence of hot flashes can be modulated by external and internal factors, including ambient temperature and fever. Rhythms of thermoregulatory and endocrine functions also may influence hot flash patterns. Examination of the interrelationships between the various systems of the body involved in hot flashes, and a multidisciplinary approach to the analysis of hot flash patterns, will aid our understanding of this complex phenomenon.  相似文献   

18.
研究了用碳粉和二氧化钛作缓冲剂同时测定乳浊料中的锆和铪的发射光谱法,选择钛作内标线,不需分离、不需化学处理,直接压样于杯形的石墨电极中,具有简便、快速、准确的特点。对测定条件、干扰因素进行了研究,从而建立测定锆和铪的新方法。锆和铪的分析线分别为327.3和286.6 nm,内标线选择为钛的308.8 nm线,锆和铪的线性范围分别为0~0.50%和0~0.25%。锆和铪的检测限分别为0.001%和0.010%,其回收率为96.67%~105.0%,当n=9时,锆的RSD为3.61%;铪的RSD为4.82%;用于样品的测定取得了满意的结果。  相似文献   

19.
Characteristic features of photochemical hole-burning (PHB) in the impurity spectra of low-temperature solids and PHB applications in molecular spectroscopy are considered. The evolution of a no-phonon hole and a phonon sidehole in excitation and fluorescence spectra is analysed on the basis of model calculations. Some more complex models for PHB are considered, which take into account reverse reactions, the optical thickness of the sample, the inhomogeneous dispersion of both homogeneous linewidths and transition energies of the photoproduct and quasi-static impurity-impurity interactions. The effects of PHB on fluorescence line narrowing are discussed. By PHB homogeneous linewidths of purely electronic and vibronic no-phonon lines in the spectra of some porphine and phthalocyanine derivatives in various matrices are measured and their temperature dependence is studied. The latter is found to be essentially different in polycrystalline and glassy matrices. Line-broadening mechanisms are discussed. By PHB the existence of an inhomogeneous distribution of vibrational frequencies in molecular impurities is established. The applications of PHB in the studies of photochemical reactions in solid solutions of phthalocyanine derivatives and tetracene are regarded and the mechanisms of these reactions are discussed. The results obtained by PHB for chlorophyll and its derivatives are presented.  相似文献   

20.
Surface chemistry of nanodiamonds   总被引:2,自引:0,他引:2  
The experimental data available in the literature and the results obtained by the author in research into the structure of nanodiamonds and the physicochemical and chemical properties of their surface are generalized. An account is given of the problems concerning the chemical state and modification of the nanodiamond surface in gaseous and liquid media and the infiuence of modification on the sorption and catalytic properties of nanodiamonds, their compactibility, and sintering. The similarity and difference in the behavior of nanodiamonds and diamond macrocrystals in oxidation processes are discussed. The activation energies of oxidation of nanodiamonds by different reagents are determined in the absence and presence of catalysts.  相似文献   

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