Combined effects of solar UV radiation and CO2-induced seawater acidification on photosynthetic carbon fixation of phytoplankton assemblages in the South China Sea

We carried out short term pCO₂/pH perturbation experiments in the coastal waters of the South China Sea to evaluate the combined effects of seawater acidification (low pH/high pCO₂) and solar UV radiation (UVR, 280–400 nm) on photosynthetic carbon fixation of phytoplankton assemblages. Under photosynthetically active radiation (PAR) alone treatments, reduced pCO² (190 ppmv) with increased pH resulted in a significant decrease in the photosynthetic carbon fixation rate (about 23%), while enriched pCO₂ (700 ppmv) with lowered pH had no significant effect on the photosynthetic performance compared to the ambient level. The apparent photosynthetic efficiency decreased under the reduced pCO₂ level, probably due to C-limitation as well as energy being diverged for up-regulation of carbon concentrating mechanisms (CCMs). In the presence of UVR, both UV-A and UV-B caused photosynthetic inhibition, though UV-A appeared to enhance the photosynthetic efficiency under lower PAR levels. UV-B caused less inhibition of photosynthesis under the reduced pCO₂ level, probably because of its contribution to the inorganic carbon (Ci)-acquisition processes. Under the seawater acidification conditions (enriched pCO₂), both UV-A and UV-B reduced the photosynthetic carbon fixation to higher extents compared to the ambient pCO₂ conditions. We conclude that solar UV and seawater acidification could synergistically inhibit photosynthesis.     

基于信息流的C2组织结构仿真评价研究

建立了C2(Command and Control)组织的信息流描述图模型与矩阵模型。从决策agent在知识、能力上的宽度与深度两个角度分析了决策agent之间进行信息交换、指挥控制命令传递的特点,在此基础上建立了C2组织中决策agent的功能模型,并定性地分析了多agent之间协同决策在决策质量、时间上的影响因素。最后针对一个简单的作战任务,从信息流的角度应用仿真方法对8种典型的C2组织结构进行了评价,仿真结果反映了C2组织结构的发展趋势。     

地区能源效率与二氧化碳排放的差异性——基于Kaya因素分解

利用绝对差异法、相对差异法和基尼系数对我国28个省区1995-2005年间能源利用效率的差异性进行了比较；引入Theil指数和Kaya因子，深入研究能源消耗导致的地区间人均CO2排放的差别；进一步将28个省区划分为八个经济区，分解Theil指数为区闭和区内贡献。结果显示（1）各省区能源利用效率存在趋同现象。（2）Theil指数表明2003年后人均C02排放差异性在减弱，Kaya因子中贡献最大的是能源强度指标，其次是人均GDP，碳排放系数贡献相对较小。交互作用因子中能源强度和人均GDP之间表现出较大的负影响，即高收入地区能源利用效率高，人均C02排放也多。（3）八个经济区间的差异要大于经济区内部的差异，且一直占据主早地位。文章结论为节能减排提供了参考。     

QoS保证的传感器网络拓扑控制算法的设计

传感器网络技术的发展对网络服务质量提出了要求,如何在满足一定的服务质量要求前提下实现能量的优化是传感器网络设计必须面对的问题。现有的相关研究主要集中在如何从路由层和链路层来保证一定的QoS指标,本工作将传感器网络中的QoS支持延伸到拓扑管理层,提出了一种支持一定QoS要求的高效的拓扑控制算法,该算法构造一种具有梯度分布特征的节点拓扑结构以平衡网络数据流在sink节点处的聚集。NS2仿真证明了该结构对QoS支持的可行性。仿真表明,该算法以较少的冗余节点增加可将延时和丢包率分别降低50%和40%,证明了该机制在高速率数据场景下的高效性。还通过NS仿真分析了算法实现中关键参数的选取原则。     

加强辅酶循环再生实现不对称合成(S)-1-苯基-1,2-乙二醇

以β-羟基苯乙酮为底物,利用羰基还原酶不对称合成(S)-1-苯基-1,2-乙二醇(PED)过程中,葡萄糖脱氢酶和6-磷酸葡萄糖脱氢酶催化NADPH再生反应与还原反应形成耦联,合成(S)PED的浓度分别达到0.78 g·L-1和0.75 g·L-1,对映体过量值(e.e.%)分别为91.84％和63.96％;连续分批还原反应后其总转化数(TTN)为26和58;经硫酸铵盐析、离子交换层析DEAE Sepharose、苯基疏水层析Phenyl Sepharose和亲和层析Blue Sepharose后得到电泳纯     

Nax Co2 O4陶瓷的力学弛豫和阻抗弛豫研究

 采用溶胶－凝胶法制备得到了γ-Na_x Co₂ O₄陶瓷,利用动态力学分析仪（DMA）在120～370 K和1～20 Hz的温度、频率范围内测量其内耗－温度谱,首次观测到γ-Na_x Co₂ O₄陶瓷在150 K附近的弛豫内耗峰,激活能为0.39 eV。采用高精度阻抗测量仪 (TH2816) 测量了γ-Na_x Co₂ O₄陶瓷在100～300 K,2 kHz～100 kHz的温度、频率范围内的阻抗－温度谱,观测到室温以下的阻抗弛豫峰,其激活能为0.13 eV,阻抗弛豫峰在外加磁场(1kGs)下向低温方向移动。这些结果表明:γ- Na_x Co₂ O₄陶瓷具有不同的力学和电学弛豫机制。     

钨、钼、钒氧化物直接合金化生产M2高速钢

论述了采用白钨矿、氧化钼和五氧化二钒代替钨铁、钼铁和钒铁冶炼W6Mo5Cr4V2 (M2 )高速工具钢的理论依据和可行性 ,介绍了冶炼工艺技术条件 ,产品性能测试和效益分析等方面的内容。实验表明 ,在中频感应炉上采用白钨矿、氧化钼和五氧化二钒直接还原合金化生产M2高速钢的新工艺顺行 ,产品化学成分合格。合金元素回收率高 ,其中 ηw97.0 8%、ηMo96 .5 1%、ηv93.79%。M2钢质量优良 ,HRC高达 6 2 .2 ,冲击韧性αk>4 9kJ cm2 ,夹杂评为 0 .5级 ,显微组织均匀、致密。而且具有显著的经济效益和社会效益 ,新工艺可以在生产中推广应用。     

Functional and physical communication between oncoproteins and tumor suppressors

The discovery of oncogenes (c-onc’s) and tumor suppressors (TS’s) has led to the concept that cancer arises from defects in each of these classes of genes or their products. More recently, it has been appreciated that c-onc and TS proteins often affect one another’s functions. Within this context, I review the two classical TS’s, p53 and the retinoblastoma protein, and the consequences of their inactivation. The various forms of genomic instability (GI) that underly the high mutation rates of transformed cells are then discussed. Particular emphasis is placed upon the concept that GI is not only an integral part of the transformed state but is a prerequisite. Increased oxidative DNA damage, and/or an inabiliy to repair it, can lead to GI. The review then discusses recent observations showing that loss of the TS protein peroxiredoxin 1 (prdx1) and increased expression of the c-onc protein c-Myc, each leads to increased oxidative DNA damage. The critical nature of the c-onc-TS interaction is underscored by that occurring between prdx1 and c-Myc, with the former protein regulating the production of DNA-damaging reactive oxygen species by the latter. The intimate association between these proteins and others serves as a paradigm for the exquisite balancing act that c-onc’s and TS’s must maintain in order to properly control normal DNA replication and cellular proliferation while simultaneously minimizing the acquisition of potentially neoplastic mutations. Received 10 May 2005; received after revision 3 July 2005; accepted 19 July 2005     

H3 PW12 O40/ZrO2-WO3催化合成己酸正丁酯

采用浸渍法制备了H3 PW12 O40/ZrO2-WO3催化剂,并通过FT-IR、XRD对其进行了表征.探讨了该催化剂对合成己酸正丁酯的催化活性,研究了不同因素对产品收率的影响.在n(正丁醇)∶n(己酸)=1.5∶1,催化剂用量为反应物总质量的1.0%,带水剂环己烷4mL,反应时间75min的条件下,己酸正丁酯的收率为84.1%.     

基于参数化分位回归模型的非寿险准备金评估

准备金及其风险边际对保险公司的偿付能力具有决定性影响.均值回归模型在非寿险准备金评估中的应用较为普遍,但需要通过Bootstrap等方法计算准备金的风险边际.分位回归模型可以一次性求得准备金及其风险边际的预测值,所以在非寿险准备金评估中具有独特的应用价值.基于GB2(Generalized Beta type 2)分布建立了一种参数化分位回归模型,该模型首先对GB2分布中的位置参数和尺度参数同时引入流量三角形数据中的事故年和进展年作为解释变量,增加了模型的灵活性;其次,根据模型参数的极大似然估计结果,借助分位数函数的表达式,计算了不同分位数水平下的准备金预测值;最后,利用极大似然估计的渐近性质,通过Delta方法给出了准备金预测值的误差.基于一组增量赔款数据的实证研究结果表明,GB2参数化分位回归模型在非寿险准备金评估及其风险边际的预测中具有良好的应用价值.