The effect of the scalar-isovector meson field on hyperon-rich neutron star matter

We investigate the effect of the calar-isovector delta-meson field on the equation of state (EOS) and composition of hyperonic neutron star matter, and the properties of hyperonic neutron stars within the frame work of the relativistic mean field theory. The influence of the delta-field turns out to be quite different and generally weaker for hyperonic neutron star matter as compared to that for npe mu neutron star matter. We find that inclusion of the delta-field enhances the strangeness content slightly and consequently moderately softens the EOS of neutron star matter in its hyperonic phase. As for the composition of hyperonic star matter, the effect of the delta-field is shown to shift the onset of the negatively-charged (positively-charged) hyperons to slightly lower (higher) densities and to enhance (reduce) their abundances. The influence of the delta-field on the maximum mass of hyperonic neutron stars is found to be fairly weak, where as inclusion of the delta-field turns out to enhance sizably both the radii and the moments of inertia of neutron stars with given masses. It is also shown that the effects of the delta-field on the properties of hyperonic neutron stars remain similar in the case of switching off the Sigma hyperons.

Properties and structure of N = Z nuclei within relativistic mean field theory

The axially deformed relativistic mean field theory with the force NLSH has been performed in the blocked BCS approximation to investigate the proper-ties and structure of N=Z nuclei from Z=20 to Z=48. Some ground state quantities such as binding energies, quadrupole deformations, one/two-nucleon separation energies, root-mean-squaxe (rms) radii of charge and neutron, and shell gaps have been calculated. The results suggest that large deformations can be found in medium-heavy nuclei with N=Z=38-42. The charge and neutron rms radii increase rapidly beyond the magic number N=Z=28 until Z=42 with increasing nucleon number, which is similar to isotope shift, yet beyond Z=42, they decrease dramatically as the structure changes greatly from Z=42 to Z=43. The evolution of shell gaps with proton number Z can be clearly observed. Besides the appearance of possible new shell closures, some conventional shell closures have been found to disappear in some region. In addition, we found that the Coulomb interaction is not strong enough to breakdown the shell structure of protons in the current region.

面向生物学对象的离子治癌模式的初步研究

目的： 肿瘤是当今人类生活中最危险的疾病之一。重离子和质子的Bragg峰，能使高吸收剂量区集中于肿瘤部位，从而有效地保护周围的健康组织，且在肿瘤照射区具有相对生物学效应高、修复效率低等特点，在放疗上比较理想。但是现有的离子束治疗模式仍是面向物理学对象的——即仅仅考虑离子的物理学特性和肿瘤的大小、形状等，很少从生物的有机整体考虑。本文依据生物学个体差异，进行了面向生物学对象的离子治疗模式必要性和可行性的基础研究。研究方法与结果： 1、不同剂量的重离子辐照肝癌SMMC-7721细胞后出现了细胞周期阻滞，细胞在低剂量区表现出明显的HRS/IRR 响应。 2、不同剂量重离子和X射线分别辐照小鼠全身后，其骨髓细胞周期表现出不同的分布，且等剂量重离子较X射线辐照对动物的影响更明显。 3、头部是一个重要的器官。重离子辐照小鼠头部后，小鼠骨髓、脾脏和外周淋巴细胞周期分布出现明显变化，这表明动物个体本身是一个有机统一整体，重离子辐照对动物非辐照部位具有直接的和间接的影响。 4、7.5c Gy重离子辐照正常小鼠后荷瘤，不仅没有能够抑制反而促进了肿瘤的生长，并且小鼠胸腺、脾脏、骨髓和外周淋巴细胞周期分布发生变化。另外发现雄性比雌性小鼠对低剂量重离子辐射更敏感。 5、以不同剂量重离子辐照荷瘤小鼠（S180肉瘤或H22肝癌）的实验中，随着剂量的增加，肿瘤细胞周期阻滞现象逐渐明显，同时出现免疫系统细胞周期的阻滞。这表明重离子辐照在杀死或引起肿瘤细胞凋亡的同时，在一定程度上也引起了正常组织和免疫系统的损伤。结论： 本研究通过一系列的细胞、动物学实验证明了面向生物学对象的离子治疗模式是可行的和必要的，这种模式将使离子治疗能够根据患者的个体差异，采取适合不同个体的最佳治疗方案，将可能极大的提高治愈率和患者的生存质量，是一种以人为本的治疗模式，有着很好的应用前景

挖掘作物抗旱节水潜力——作物对多变低水环境的适应与调节

本文针对半干旱地区多变低水的实际田间环境,讨论了作物对不同干旱类型的反应,适度干旱后复水的生理补偿效应,不同类型作物在干湿交替条件下的差异,以及增强作物对多变水环境适应的技术.同时,就多变低水环境的概念、作物对多变低水环境的适应机理以及作物抗旱生理研究与旱农生产实际相衔接等问题提出了若干看法.

不同比例尺DEM提取地面坡度的精度研究——以在黄土丘陵沟壑区的试验为例

以陕北绥德县韭园沟流域为试验样区 ,采用高精度 1∶ 1万 DEM所提取的坡度为准值 ,应用多层面复合分析和比较分析的方法 ,研究该地区 1∶ 5万 DEM提取地面坡度的误差特征与纠正方法。试验结果显示 ,所获得的不同空间尺度下 DEM所提取坡度值的转换图谱 ,可对 1∶ 5万 DEM计算的地面坡度统计值进行有效修正。该成果对于 DEM数据在水土保持领域若干应用标准的制定 ,提供了重要的理论依据与技术路线

资源流动的环境效应(英文)

21世纪,中国的人口和经济的持续增长面临着资源短缺和生态脆弱的限制。提高资源利用效率和消减资源利用引起的环境影响是学术界和决策者面临的新课题。本文从资源流动的视角研究资源利用过程及其引起的环境影响。我们把资源流动过程分解为开采、加工、转化、消费等几个关键环节,评价其资源利用效率和环境影响,并寻求改善的途径。因其资源消耗量大、生态环境影响严重,我们选取了林木、煤炭及石油研究其资源与产品流动及其环境影响。林木产品的产量、进出口量和消费量数据来自中国森林统计年鉴(1949-2001)。煤炭、石油的开采量、进出口

A data-model fusion approach for upscaling gross ecosystem productivity to the landscape scale based on remote sensing and flux footprint modelling

Chinese Academy of Sciences ; National Science Foundation of China [41071059]; National Key Technology R&D Program of China [2008BAK50B06-02]; National Basic Research Program of China [2010CB950900, 2010CB950704]; Natural Sciences and Engineering Research Council of Canada

DECODE: a new method for discovering clusters of different densities in spatial data

National Key Basic Research and Development Program of China [2006CB701305]; State Key Laboratory of Resource and Environment Information System [088RA400SA]; Chinese Academy of Sciences

Spatial and temporal flows of China's forest resources: Development of a framework for evaluating resource efficiency

Science & Technology Basic Work Program of China: Scientific Survey of the Middle-lower Reaches of Lantsang River and the Great Shangri-La Region [2008FY110300]; National Basic Research Program of China (973 Program): Ecosystem Services and Ecological Safety of the Major Terrestrial Ecosystems of China [2009CB421106]; National Natural Science Foundation of China [30670374]; EU ; European Commission, DG Research [003874]

Spatial patterns and driving forces of land use change in China during the early 21st century

Land use and land cover change as the core of coupled human-environment systems has become a potential field of land change science (LCS) in the study of global environmental change. Based on remotely sensed data of land use change with a spatial resolution of 1 km x 1 km on national scale among every 5 years, this paper designed a new dynamic regionalization according to the comprehensive characteristics of land use change including regional differentiation, physical, economic, and macro-policy factors as well. Spatial pattern of land use change and its driving forces were investigated in China in the early 21st century. To sum up, land use change pattern of this period was characterized by rapid changes in the whole country. Over the agricultural zones, e.g., Huang-Huai-Hai Plain, the southeast coastal areas and Sichuan Basin, a great proportion of fine arable land were engrossed owing to considerable expansion of the built-up and residential areas, resulting in decrease of paddy land area in southern China. The development of oasis agriculture in Northwest China and the reclamation in Northeast China led to a slight increase in arable land area in northern China. Due to the "Grain for Green" policy, forest area was significantly increased in the middle and western developing regions, where the vegetation coverage was substantially enlarged, likewise. This paper argued the main driving forces as the implementation of the strategy on land use and regional development, such as policies of "Western Development", "Revitalization of Northeast", coupled with rapidly economic development during this period.

Effects of temperature, glucose and inorganic nitrogen inputs on carbon mineralization in a Tibetan alpine meadow soil

High levels of available nitrogen (N) and carbon (C) have the potential to increase soil N and C mineralization We hypothesized that with an external labile C or N supply alpine meadow soil will have a significantly higher C mineralization potential and that temperature sensitivity of C mineralization will increase To test the hypotheses an incubation experiment was conducted with two doses of N or C supply at temperature of 5 15 and 25 C Results showed external N supply had no significant effect on CO2 emission However external C supply increased CO2 emission Temperature coefficient (Q(10)) ranged from 113 to 1 29 Significantly higher values were measured with C than with N addition and control treatment Temperature dependence of C mineralization was well-represented by exponential functions Under the control CO2 efflux rate was 425 g CO2-Cm-2 year(-1) comparable to the in situ measurement of 422 g CO2-Cm-2 year(-1) We demonstrated if N is disregarded microbial decomposition is primarily limited by lack of labile C It is predicted that labile C supply would further increase CO2 efflux from the alpine meadow soil (C) 2010 Elsevier Masson SAS All rights reserved

Luminescence and its temperature effects on Sm2+ in alkaline earth borates

The luminescence of Sm2+ in alkaline earth berates (BaB8O13, SrB4O7 and SrB6O10) is reported. The temperature effects on luminescence and decay time of Sm2+ are studied. Due to the thermal population, D-5(1) --> F-7(J) transitions of Sm2+ in BaB8O13, SrB4O7 and SrB6O10 are observed at room temperature. The f-d broad emission transitions of Sm2+ in SrB4O7 and SrB6O10 are observed at high temperature whereas no f-d transition is observed in BaB8O13.

The origin of nonlinearities in K[B5O6(OH)(4)]center dot 2H(2)O crystal

In this paper the origin of nonlinearities of the K[B5O6(OH)(4)].2H(2)O(KB5) crystal has been investigated from a comprehensive view-point by using the bond-valence theory of complex crystals. The results of the calculation (d(31) = -1.18 X 10(-10) esu, d(32) = 0.20 X 10(-10) and d(33) = -1.03 X 10(-9) esu) are in good agreement with experimental data. For the first time we pointed out that its nonlinearities come from the H(2)-O(2) bonds and the [B5O6(OH)(4)](-) group, and estimated its larger nonlinear optical (NLO) coefficient d(33).

Luminescence of Pb2+ and energy transfer from Pb2+ to rare earth ions in silicate oxyapatites

The Pb2+ luminescence in a series of silicate oxyapatites Me(2)(Y, Gd)(8)(SiO4)(6)O-2, Me(4)Y(6)(SiO4)(6)O (Me = Mg: Ca, Sr) is reported and discussed in relation to the crystal structure. The maximum wavelengths of the excitation (S-1(0)-P-3(1)) and emission (P-3(1)-S-1(0)) bands of Pb2+ are independent of the Mc:Y ratio (2:8 or 4:6) but they have lower energies in MgY-oxyapatites than in CaY- and SrY-oxyapatites. The Stokes shift of Pb2+ luminescence amounts to 11 100 to 11 400 cm(-1): which does not depend strongly on the host composition. There exists a mutual energy transfer between Pb2+ and Gd3+ in Sr2Gd8(SiO4)(6)O-2. At last, the dependence of the energy transfer efficiency of Pb2+-Sm3+, Tb3+: Dy3+ in Sr-2(La: Gd)(8)(SiO4)(6)O-2 and Ca-2(Y, Gd)(8)(SiO4)(6)O-2 on their doping concentrations was studied in more detail.