Spatial and seasonal distributions of carbonaceous aerosols over China

IEECAS SKLLQG

Theoretical study on properties of new isotope (265)Bh

The properties of nuclei belonging to the newly observed a-decay chain starting from (265)Bh have been studied. The axially deformed relativistic mean-field calculation with the force NL-Z2 has been performed in the blocked BCS approximation. Some ground state properties such as binding energies, deformations, spins, and parities, as well as Q-values of the alpha-decay for this decay chain have been calculated and compared with known experimental data. Good agreement is found. The single-particle spectrum of the nucleus (265)Bh is studied and some new magic numbers are found, while the magnitudes of the shell gaps in superheavy nuclei are much smaller than those of nuclei before the actinium region, and the Fermi surfaces are close to the continuum. Thus the superheavy nuclei are usually not stable. The alpha-decay lifetimes in the (265)Bh decay chain are evaluated by different formulae, and compared with experimental data. The methods which give good agreement with the data are selected.

Radiosensitivity to high energy iron ions is influenced by heterozygosity for Atm, Rad9 and Brca1

Loss of function of DNA repair genes has been implicated in the development of many types of cancer. In the last several years, heterozygosity leading to haploinsufficiency for proteins involved in DNA repair was shown to play a role in genomic instability and carcinogenesis after DNA damage is induced, for example by ionizing radiation. Since the effect of heterozygosity for one gene is relatively small, we hypothesize that predisposition to cancer could be a result of the additive effect of heterozygosity for two or more genes critical to pathways that control DNA damage signaling, repair or apoptosis. We investigated the role of heterozygosity for Aim, Rad9 and Brad on cell oncogenic transformation and cell survival induced by 1 GeV/n Fe-56 ions. Our results show that cells heterozygous for both Aim and Rad9 or A tin and Brca1 have high survival rates and are more sensitive to transformation by high energy iron ions when compared with wild-type controls or cells haploinsufficient for only one of these proteins. Since mutations or polymorphisms for similar genes exist in a small percentage of the human population, we have identified a radiosensitive sub-population. This finding has several implications. First, the existence of a radiosensitive sub-population may distort the shape of the dose response relationship. Second, it would not be ethical to put exceptionally radiosensitive individuals into a setting where they may potentially be exposed to substantial doses of radiation. (C) 2010 COSPAR. Published by Elsevier Ltd. All rights reserved.

长白山各植被带主要树种凋落物分解速率及模型模拟的试验研究

2001～2003年在长白山自然保护区内3个垂直植被带的典型群落红松阔叶林、云冷杉林和岳桦林内,利用网袋埋藏法对群落内的6个主要优势乔木树种凋落物进行埋藏分解试验,研究凋落物分解速率及其变化动态;同时利用分解模型,模拟预测凋落物的分解进展,为深入研究这6个树种的营养策略、群落养分循环等奠定基础,也为森林生态系统管理提供理论依据。研究结果表明,所研究的6个树种凋落物都表现出随时间进程失重率增大的现象,但失重率并不与时间呈线性相关。在分解的638d(1.75a)后,6种叶凋落物的分解速率明显升高。到分解实验结止时(699d),叶凋落物干重剩余率从小至大依次为白桦(24.56%)、紫椴(24.81%)、红松(38.48%)、鱼鳞云杉(41.15%)、岳桦(41.53%)和臭冷杉(42.62%)。枝凋落物分解速率明显低于叶,枝干重剩余率从小至大依次为紫椴(44.98%)、臭冷杉(64.62%)、红松(72.07%)、鱼鳞云杉(73.51%)、白桦(77.37%)和岳桦(80.35%)。在同一海拔高度,阔叶树种叶凋落物分解速率大于针叶树种。并且随着海拔的升高,叶凋落物分解速率逐渐减慢。模型分析预测结果表明,长白山北坡各垂直植被带的优势树种叶凋落物分解95%需4.5～8.0a;年分解系数为紫椴(0.686)>白桦(0.624)>红松(0.441)>鱼鳞云杉(0.406)>臭冷杉(0.397)>岳桦(0.385);枝凋落物分解95%需7.8～29.3a,不同树种间的差异明显。枝年分解系数为紫椴(0.391)>臭冷杉(0.204)>红松(0.176)>鱼鳞云杉(0.157)>白桦(0.148)>岳桦(0.102)。

长白山生物圈保护区旅游的环境影响研究

生态旅游可以简单地定义为发生在那些具有独特的风景、特殊的生态学价值和具有纯粹自然性的受保护区域的旅游活动，也可以被理解为广义旅游的一部分，即可为自然和文化资源保护提供经济支持的一种旅游。根据生态旅游协会的定义（１９９１），生态旅游是一种前往自然区域以...

短刺小克银汉霉菌丝球对孔雀绿的吸附研究

利用分离得到的短刺小克银汉霉对三苯甲烷类染料孔雀绿进行了吸附脱色研究。当染料质量浓度为100mg·L-1时,短刺小克银汉霉菌丝球能在3h内使孔雀绿脱色率达到92%以上。在通气脱色体系中研究了短刺小克银汉霉菌丝球在不同pH、脱色温度、摇床转速等条件下对孔雀绿脱色效果的影响。研究结果表明,短刺小克银汉霉菌丝球在温度为35℃,pH为10,转速为150r·min-1的条件下对孔雀绿具有最大脱色率,脱色时间在180min时达到吸附平衡。孔雀绿质量浓度为25～100mg·L-1,小克银汉霉菌丝球对孔雀绿吸附脱色动力学符合拟二级动力学方程(R2>0.99)。菌丝球对孔雀绿的吸附符合Langmuir等温吸附方程(R2>0.998),饱和吸附量达到1250mg·g-1。对吸附了染料的菌体进行解吸研究,发现用异戊醇作为解吸剂的解吸率最高,可以达到93%,解吸过程符合二级动力学方程(R2>0.99)。

冷季型草坪草对高温胁迫的生理生态适应机理研究进展

高温是制约草坪草(尤其是冷季型草坪草)生长的重要生态因子之一。然而,草坪草本身都具有一定的耐热性,特别是通过其体内的一些生理和生化机制能够抵御和适应一定程度和时间的热胁迫,比如通过植物体内细胞膜膜脂组分的变化、抗氧化系统对氧自由基的清除、热激蛋白的合成以及一些其它物质代谢的渗透调节以获得耐热性,从而缓减高温对其的伤害。本文结合作者数年的研究成果,就这两个方面综述了国内外的研究进展并提出了目前有关这些方面研究的不足以及今后研究的重点,以便为揭示冷季型草坪草在夏季所受高温伤害机理以及热适应机理提供科学的理论依据和实践指导。

黄土塬区三种豆科牧草的竞争生长

通过田间试验研究了沙打旺、紫花苜蓿和达乌里胡枝子3种豆科牧草在黄土旱塬以不同密度单播、混播时的竞争生长能力及水分利用效率。单播时苜蓿生长次年3个密度的生产力分别为15349kg·hm-2、20582kg·hm-2、21531kg·hm-2,沙打旺和胡枝子3个密度的生产力分别为7979kg·hm-2、16 440 kg·hm-2、21055kg·hm-2和2412kg·hm-2、5270kg·hm-2、7102kg·hm-2。混播草地生产力以苜蓿+胡枝子最高(平均19227kg·hm-2),沙打旺与胡枝子混播的生产力最低(平均11977kg·hm-2)。和生产力较高的参混种苜蓿、沙打旺单播相比,苜蓿与沙打旺混播及沙打旺与胡枝子混播的生产力在3种密度下均有不同程度的降低。苜蓿主根下扎深度2m,0~60cm根系占总根量的66%,沙打旺和胡枝子根系最大下扎深度分别为1.8 m和1.5m,0~60cm根系占总根量比例分别是80%、91%。3种牧草中苜蓿的平均水分利用效率最高,为25.75kg·mm-1·hm-2,胡枝子最低为7.71kg·mm-1·hm-2,沙打旺居中。苜蓿群体种内个体间竞争强度高于沙打旺和胡枝子。结果...

两种五倍子蚜虫冬寄主藓类植物的光合特性及其与光照、温度和植物体水分含量变化的关系

使用CI 30 1PS (CIDInc .USA )对生长于冬季和春季的大羽藓 (Thuidiumcymbifolium )与垂藓(Chrysocladiumretrorsum )的净光合速率 (Pn)及其与光照、温度和植物体水分含量的关系进行了研究 .结果表明 ,大羽藓和垂藓的光合能力分别达到 14 1和 117μmolCO2 kg-1·dw·s-1,光合能力从冬季到春季呈上升趋势 .这两种藓类植物的光响应曲线比较相似 ,光饱和点高达 80 0～ 90 0 μmol·m-2 s-1,光补偿点为 40～ 5 0 μmol·m-2s-1,光合作用最适温度在春季为 2 5～ 36℃ ,而冬季为 2 0～ 30℃ .同时对于低温又具有很强的抗性 ,在冰点以下的温度条件下 (-15～ 0℃ )能够保持一定的净光合 .净光合速率的水分响应曲线表明 ,这两种藓类的最适水分含量为 2 0 0～ 30 0 (4 0 0 ) %dw ,水分含量降低到 15 0 %dw时光合作用开始受到抑制 ,在 40 %～ 5 0 %dw时净光合降低到零或略变为负数 .结果表明 ,大羽藓和垂藓都属于耐干旱、强阳性的藓类 ,但垂藓在这几个方面略逊于大羽藓 .