恒星内部电荷屏蔽对β衰变率的影响     

孙庆强  黄增光  朴红光  罗志全 《天文学进展》2006,24(4):380-386

针对低能反应和共振跃迁,分析了在恒星内部电荷屏蔽对β衰变率的影响．对共振跃迁的分析是基于核的壳层模型．作为例子,详细计算了电荷屏蔽对56Cr的β衰变的影响．结果表明:在较低温度和高密度下,电荷屏蔽使β衰变率有明显的增加。这对恒星晚期演化和超新星爆发研究可能会有重要的影响。  相似文献   

Study on application of polyenzyme method to offal of Harengula zunasi     

Deng Shanggui  Yang Ping  Xia Xingzhou 《中国海洋湖沼学报》2003,21(4):312-318

The new polyenzyme method for making gravy fromHarengula zunasi offal involves protein enzymolysis with flavorase after proper alkaline and neutral protease levels were established by orthogonal trials to select the best hydrolytic conditions for processing offal with alkaline and neutral protease. The conditions for the polyenzyme method were pH of 7.0, temperature of 50°C, alkaline and neutral protease concentration of 1.5% respectively, hydrolysis time of 120 min, and flavorase concentration of 2.0%, for 60 min. The new gravy-making technology yields a nutritious and delicious gravy containing 40.3% of total essential amino acids, with delicious amino acids Glu, Asp, Gly, Ala, Pro and Ser comprising 49.5%, total and amino nitrogen being respectively 1.9 and 1.1 g/100 g (amino acid nitrogen being 61.0% of total nitrogen), The polyenzyme method was used to make 14.8% protein gravy fromHarengula zunasi offal. In addition, inorganic elements, the phosphorus content is the highest. This project was aided financially by the Guangdong Science and Technology Office (No. 2KM06002S).  相似文献   

NEMERTEANS OF ZHOUSHAN ISLANDS, EAST CHINA SEA COAST,CHINA Ⅰ.ENOPLA: DISTROMATOPHYNCHOCOELA: MONOSTILIFERA: EMPLECTONEMERTIDAE     

孙世春 《中国海洋湖沼学报》1995,(2)

Two nemerteans of the Zhoushan Islands, Paranemertes sinensis sp. nov. and P. peregrina, are reportedin this paper. P. sinensis sp. nov. has the body wall longitudinal musculature anteriorly divided,numerous eyes grouped into four clusters, two pairs of cephalic furrows, rhynchocoel 1/3 to 1/2 of fullbody length, cephalic glands well developed and posteriorly extending beyond the cerebral ganglia.precerebral septum absent, cerebral sense organs situated in front of brain, three pairs of nephridiopores,and 17-18 proboscis nerves.  相似文献   

ISOLATION, PURIFICATION AND CHARACTERIZATION OF THE HYDROGEN EVOLUTION PROMOTING FACTOR OF HYDROGENASE OF SPIRULINA PLATENSIS     

顾天青  张惠苗  孙世华 《中国海洋湖沼学报》1996,(1)

A component (s-factor) with obvious promoting effect on hydrogen evolution of hydrogenase has beenisolated and extracted from a Cell=free preparation of Spirulina platensis.The effect of the s-factor in the re-action system is similar to that of Na_2S_2O_4, but is coupled with ligh. The s-factor has the maximumabsorption peak at 620 nm in the oxidized state, at 590 nm in the reduced state. The partially purifieds-factor showed two bands by SDS-PAGE and is distinctly different from phycocyanin,which has nochange of oxidized state and reduced state absorption spectra, and also has no promoting effect onhydrogenase of Spirulina platensis under the light.  相似文献   

原子钟噪声的蒙特卡络模拟方法   总被引：1，自引：0，他引：1  

孙宏伟 《时间频率学报》1996,19(1):33-37

讨论了原子钟噪声的蒙特卡络模拟方法．具体过程是：先产生模拟所需的正态分布随机数，从实际钟的阿仑方差估算出噪声电平，然后用１组递点函数产生高质量的模拟钟时差的随机序列．在对１台商品铯钟进行具体模拟后，给出了真实数据与模拟值的阿仑方差之问的相符程度，最后对实际问题进行了分析．  相似文献   

时空概念中的椭球改正     

夏哲仁 《测绘学报》1991,20(3):190-200

  相似文献   

安徽省黄山地区唐家坞组生物地层   总被引：2，自引：0，他引：2  

孙乘云  杜森官  王有生 《地层学杂志》2008,32(3)

安徽省南部黄山市刘村一带唐家坞组的时代以往归为晚志留世,新近在唐家坞组中采获腕足类、瓣鳃类、腹足类等多门类化石,并首次采获胞石、鹦鹉螺等化石,其中胞石Conochitina(Densichitana)dens的时代为兰多维列世末至文洛克世初期,含这些化石的层位相当于秀山动物群的层位。结合地质情况分析,唐家坞组时限主要属于早志留世。  相似文献   

徐州土壤多环芳烃的环境地球化学迁移特征   总被引：1，自引：1，他引：0  

葛晓立  焦杏春  袁欣  李奇  罗松光  孙玮琳 《岩矿测试》2008,27(6):409-412

选择江苏徐州黄棕壤进行不同深度层位多环芳烃含量的定量分析,研究并探讨了多环芳烃在土壤深度剖面中的地球化学迁移特征。研究结果显示,多环芳烃在徐州土壤剖面中主要集中在地表0~20 cm内。其中低环多环芳烃化合物的迁移能力较强,4~6环等高环化合物相对较难迁移,主要残留于地表生态系统环境中。  相似文献   

对松辽盆地钱家店凹陷铀成矿作用的重新认认识     

陈晓林  方锡珩  郭庆银  夏毓亮  庞雅庆  孙晔 《地质学报》2008,82(4):553-561

钱家店凹陷中的含矿层位主要为上白垩统姚家组,前人认为其中的红色砂岩为原生成因,但大量的证据证实砂岩原生应以灰色为主,红色砂岩为后生氧化蚀变造成,并控制着钱家店铀矿床铀矿化的产出.在此基础上建立该矿床的后生蚀变分带,依次为红色蚀变带、黄色蚀变带、灰白色蚀变带、过渡带、原生带,红色蚀变带为主要的氧化带,铀矿化主要集中在过渡带.平面上铀矿化主要分布于层间氧化带前锋线附近的位置,并在氧化舌状体的前端和两个氧化舌状体之间存在铀的富集.文章最后还建立了该矿床的成矿模式,并对区域上层间氧化带的展布进行了讨论.  相似文献   

Dehydration and melting during continental collision: Constraints from element and isotope geochemistry of low-T/UHP granitic gneiss in the Dabie orogen     

Qiong-Xia Xia  Yong-Fei Zheng  Li-Gang Zhou 《Chemical Geology》2008,247(1-2):36-65

A combined study of petrography, whole-rock major and trace elements as well as Rb?Sr and Sm?Nd isotopes, and mineral oxygen isotopes was carried out for two groups of low-T/UHP granitic gneiss in the Dabie orogen. The results demonstrate that metamorphic dehydration and partial melting occurred during exhumation of deeply subducted continent. Zircon δ¹⁸O values of ? 2.8 to + 4.7‰ for the gneiss are all lower than normal mantle values of 5.3 ± 0.3‰, consistent with ¹⁸O depletion of protolith due to high-T meteoric-hydrothermal alteration at mid-Neoproterozoic. Most samples have extremely low ⁸⁷Sr/⁸⁶Sr ratios at t₁ = 780 Ma, but very high ⁸⁷Sr/⁸⁶Sr ratios at t₂ = 230 Ma. This suggests intensive fluid disturbance due to the hydrothermal alteration of protoliths during Neoproterozoic magma emplacement and the metamorphic dehydration during Triassic continental collision. Rb–Sr isotopes, Th/Ta vs. La/Ta and Th/Hf vs. La/Nb relationships suggest that Group I gneiss experienced lower degrees of hydrothermal alteration, but higher degrees of dehydration, than Group II gneiss. The two groups of gneiss have similar patterns of REE and trace element partition. Group I gneiss displays good correlations between Nb and LREEs but no correlations between Nb and LILEs (Rb, Ba, Pb, Th and U), indicating differential mobilities of LILEs during the dehydration. Thus the correlation between Nb and LREEs is inherited from protolith rather than caused by metamorphic modification. Relative to Group I gneiss, Group II gneiss has stronger negative Eu anomaly, lower contents of Sr and Ba but higher contents of Rb, Th and U. In particular, Nb correlates with LILEs (e.g., Rb, Sr, Ba, Th and U), but not with LREEs (La and Ce). This may indicate decoupling between the dehydration and LILEs transport during continental collision. Furthermore, dehydration melting may have occurred due to breakdown of muscovite during “hot” exhumation. Group II gneiss has extremely low contents of FeO + MgO + TiO₂ (1.04 to 2.08 wt.%), high SiO₂ contents of 75.33 to 78.23 wt%, and high total alkali (Na₂O + K₂O) contents (7.52 to 8.92 wt.%), comparable with compositions predicted from partial melting of felsic rocks by experimental studies. Almost no UHP metamorphic minerals survived; felsic veins of fine-grain minerals occurs locally between coarse-grain minerals, resulting in a kind of metatexite migmatites due to dehydration melting without considerable escape of felsic melts from the host gneiss. In contrast, Group I gneiss only shows metamorphic dehydration. Therefore, the two groups of gneiss show contrasting behaviors of fluid–rock interaction during the continental collision.  相似文献