首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 531 毫秒
1.
利用快中子位置灵敏谱仪,伴随粒子飞行时间方法,在3°~15°角区测量了14.7MeV中子在Ta核上弹性散射的微分截面,并将实验数值与理论计算值进行了比较。  相似文献   

2.
高能核一核碰撞中靶核和射弹核的碎片分布,是研究核碎裂机制的重要方面.通过对500AMeV^56e与原子核乳胶相互作用产生的靶核碎片的角分布的测量,可以发现重靶AgBr的黑粒子的发射角关于90°方向近似对称,即表明在90°方向存在侧向流.我们知道黑粒子是从激发的剩余靶核蒸发出来的,从流体力学模型的角度上来看,侧向流产生原因可能是弹核旁观体的弹出与弹核参加者产生侧向集体流造成了靶核旁观体向相反方向运动,从而在接近90°的方向上产生靶核碎片集体流.  相似文献   

3.
高温气冷堆一回路的放射性物质主要取决于包覆燃料颗粒在燃料元件制造过程中和辐照条件下的破损率,畸形UO2芯核(椭球状、带小尾巴形和连体等)是燃料元件制造过程中包覆燃料颗粒发生破损的主要原因之一,因此燃料元件设计中,畸形UO2芯核的份额要求小于1×10-4,即在95%的置信度下,在随机抽取的近30000个UO2芯核中不允许有1个畸形芯核。报道了检查畸形芯核的抽样方案和检验方法,该方法是将随机抽取的样品通过一块平板,控制平板的倾斜度、振幅和频率,可以有效地将畸形芯核从样品中分离出来。实践表明该方法速度快,结果可靠,将用于10MW高温气冷堆燃料元件的生产。  相似文献   

4.
再生核空间算子样条插值函数   总被引:1,自引:0,他引:1  
在具体的再生核空间H^10中,解出了再生核的解析表达式,并建立了空间H^10中的微分算子样条插值函数与再生核的联系,丰富了再生核空间微分算子样条函数的一系列重要性质。  相似文献   

5.
考虑到高能核-核碰撞中反应系统的纵向扩展,用热化柱图象对簇射粒子的赝快度分布进行了描述,计算结果与10^0-10^5AGeV能区的实验数据符合。  相似文献   

6.
在再生核空间H^10中,以其再生核作为插值逼近的基函数,构造了分段再生核插值函数,并讨论了该插值函数的最佳性质。  相似文献   

7.
用伴随粒子飞行时间方法,在1.7°至25°范围内测量了14.2MeV中子在铅核上的弹性散射微分截面.用蒙特卡罗方法对中子在样品中的注量衰减,多次散射及有限角分辨做了修正.实验结果与其它测量及球形核光学模型作了比较.  相似文献   

8.
目的:研究人类精子染色体畸变。方法:E和3号染色体涂染探针对人类精子间期核进行荧光原位杂交,共检测了10名正常健康男性,2名涉及3号染色体平衡易位携带t(3:7)、t(3:9)的精子。结果:正常男性精子间期核中3号染色数目和(或)结构畸变率〈2%,涉及3号染色体平衡易位携带的畸变率〉10%。结论:荧光原位杂交技术可秀于检测精子间期核染色体的畸变.  相似文献   

9.
 核数据特别是中子核数据是核物理基础研究、核能开发与利用以及核技术发展的基础数据,是连接核物理基础研究与核技术应用的重要桥梁,其质量直接关系到与核相关产品的有效性、安全性与经济性。概述了核数据、核数据用途以及国内外核数据发展动态,分析了国内核数据工作发展的差距,总结了国外相关核数据工作经验以及给中国核数据工作带来的启示,提出了在现有基础上如何发展中国的核数据研究工作的建议。  相似文献   

10.
对1990~1991年在江苏海州湾水域(119°10'~120°10'E,34°0'~35°10'N)采集的标本进行鉴定,共有18种,隶属12科14属.其中水螅水母类16种,栉水母类2种.其种类组成以暖温带近岸低盐种为主.在海州湾四个季度均有水母出现,分布范围较广,遍布本次调查海区各个站位,密集区位于119°20'~119°30'E,34°40'~35°00'N之间的海域.分布面以5月和8月最广,密集度也高,尤以5月的个体生物最最高,8月次之,11月和2月较少.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

19.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号