Eutrophication,health risk assessment and spatial analysis of water quality in Gucheng Lake,China

The water characteristics of the Gucheng Lake, such as eutrophication, health and spatial distribution, were investigated. On the basis of the trophic state index (TSI) and entropy weight, a synthesized trophic state index (STSI) model was established to assess lake eutrophication condition through calculating STSI, choosing TP, TN, COD, BOD and NH₃-N as trophic variables. The STSI ranged from 50.58 to 62.44, which showed that the water has been between eutrophic and supereutrophic. A histogram was applied to health risk assessment which was analyzed from carcinogenic substances (Cr⁺⁶, As and Cd) and non-carcinogenic substances (hydroxybenzene, Pb, Hg, CN⁻ and NH₃), and the results showed that the former was much greater than the latter for effect. The total risk for each resident caused by all pollutants ranged from 5.18E-05 to 8.34E-05, which is far higher than the standard, recommended by Sweden Bureau of Environment Protection and Holland Ministry of Building and Environment Protection (1.0E-05). Cluster analysis was used to detect similarities and dissimilarities among the seven sampling sites and explain the observed clustering in terms of affected conditions. Twenty-one variables were used to divide seven sampling sites into three groups, namely, north lake, south lake and lake center.     

基于FS系统对乌鲁木齐VLBI射电望远镜进行天线测量

在天文观测中射电望远镜性能参数的好坏直接影响到观测数据质量,为了保证观测质量,提高观测效率,需要对天线性能进行测量.当前进行天线测量的方法有场地测量法和射电天文法,不同的方法应用范围和效果不同.对于大型天线而言采用射电天文法进行天线测量高效快捷.针对VLBI射电望远镜,介绍了使用终端FS系统对天线参数进行测量（基于射电天文法）的方法和过程,以乌鲁木齐南山25 m天线增益和指向精度测量作为范例,重点叙述了测量的方法和步骤,并对该方法进行了讨论.     

A method for aligning the plastic scintillator detector on DAMPE

The Plastic Scintillator Detector(PSD) onboard the DArk Matter Particle Explorer(DAMPE)is designed to measure cosmic ray charge(Z) and to act as a veto detector for gamma ray identification.To fully exploit the charge identification potential of PSD and to enhance its capability to identify gamma ray events, we develop an alignment method for the PSD. The path length of a given track in the volume of a PSD bar is derived taking into account the shift and rotation alignment corrections. By examining energy spectra of corner-passing events and fully contained events, position shifts and rotations of all PSD bars are obtained, and are found to be on average about 1 mm and 0.0015 radian respectively. To validate the alignment method, we introduce artificial shifts and rotations of PSD bars into the detector simulation.These shift and rotation parameters can be recovered successfully by the alignment procedure. As a result of the PSD alignment procedure, the charge resolution of the PSD is improved from 4% to 8%, depending on the nuclei.     

海底孔内水合物观测系统与钻井实施

通过耦合布设海底表面和孔内水合物观测系统获取物理、化学、微生物等数据是了解掌握海洋水合物环境动态变化、碳循环规律和资源开发技术的有效手段,据此初步提出了一套海底孔内水合物观测系统,并指出了系统的关键技术难点。而在钻井布设该孔内观测系统时,要注意防止井内安全事故的发生,充分评估安放位置处含水合物地层的地质力学稳定性并采取适当的钻井和完井方式稳定或强化含水合物地层以支撑孔内观察仪器,实现孔内长期监测。最后讨论了在我国南海实施孔内水合物观测系统的必要性,并提出了初步想法。     

Studies on ultrastructure of oocyte in process of maturing in pen shell

The present paper deals with the ultrastructural changes of oocyte in the process of maturing in pen shell Atrinapectinata Linne. When it develops from the antecedent growth period to the accelerating growth period the annulate lamellae emerge, the RER better develop, the yolk granules with single and double layer membrane and are visible. In the well-developed mitochondria there is yolk stored. The Golgi vacuoles are brewing yolk granules. At the mature period the annulate lamellae and the Golgi bodies disappear, and there are only a few RER and mitochondria with poor cristae in the cytoplasm. All these might be well used for judging the maturity of the ootids in the process of the artificial propagation.     

不同营养条件下铜绿微囊藻(Microcystis aeruginosa)和小球藻(Chlorella vulgaris)的生长竞争行为

蓝藻的暴发通常是藻类之间竞争的结果,了解环境中蓝藻与其它藻类的竞争特点和生存策略对揭示藻华暴发的机制及治理具有重要意义。本文以营养竞争为例,以铜绿微囊藻(Microcystis aeruginosa)和小球藻(Chlorella vulgaris)为受试对象,通过测定细胞密度、胞内C、N、P、S四种主要元素含量以及培养基中总氮(TN)、总磷(TP)的消耗,研究不同营养等级(超富营养、富营养、中营养、贫营养)以及单独N、P限制下两种藻在单独培养和共生培养条件下的生长特征和竞争行为。结果表明:(1)在超富营养、富营养、中营养、贫营养条件时,单独培养下的两种藻生物量与营养丰富程度呈正相关;(2)共培养条件下,在高营养水平时铜绿微囊藻在竞争中占优势,低营养水平时小球藻具有竞争优势;(3)胞内C、N、P、S的测定发现,随着营养水平的下降,两种藻胞内N、P的百分含量逐渐减少,而C、S并未呈现显著变化;(4)N限制时,铜绿微囊藻的半饱和常数Ks及最大比增长率μmax均大于小球藻;P限制条件下铜绿微囊藻的半饱和常数Ks小于小球藻,而最大比增长率μmax大于小球藻。综合分析,同一营养条件下,铜绿微囊藻竞争优势的先决因子是N,小球藻是P。因此,从营养竞争与生物适应力角度考虑,降低水体中富余的N或适当提高P的浓度可让小球藻获得竞争优势,对限制单一物种的形成具有平衡作用,可作为防治藻华的潜在方法。     

两维银河系旋臂对比度

为改善文献上惯用的表现银河系分子谱线巡视结果的完全平滑了方位信息的径向分布方法,我们发展了原子气体或分子云参量的分环银经分布图,(X—l)_i图,它在某种程度上给出了方位信息。用现存旋臂模型结合这种图我们得到的银道面旋臂区和臂间区的E(HI),E(CO),E(~(13)CO)和N/S(~(13)CO)的两维对比度约为1—2。     

An algorithm to resolve γ-rays from charged cosmic rays with DAMPE

The DArk Matter Particle Explorer(DAMPE),also known as Wukong in China,which was launched on 2015 December 17,is a new high energy cosmic ray and γ-ray satellite-borne observatory.One of the main scientific goals of DAMPE is to observe Ge V-Te V high energy γ-rays with accurate energy,angular and time resolution,to indirectly search for dark matter particles and for the study of high energy astrophysics. Due to the comparatively higher fluxes of charged cosmic rays with respect to γ-rays,it is challenging to identify γ-rays with sufficiently high efficiency,minimizing the amount of charged cosmic ray contamination. In this work we present a method to identify γ-rays in DAMPE data based on Monte Carlo simulations,using the powerful electromagnetic/hadronic shower discrimination provided by the calorimeter and the veto detection of charged particles provided by the plastic scintillation detector. Monte Carlo simulations show that after this selection the number of electrons and protons that contaminate the selected γ-ray events at～10 Ge V amounts to less than 1% of the selected sample.Finally,we use flight data to verify the effectiveness of the method by highlighting known γ-ray sources in the sky and by reconstructing preliminary light curves of the Geminga pulsar.     

凡纳滨对虾P23蛋白基因的筛选、表达和生物信息学分析

克隆凡纳滨对虾极端体重个体的组织差异表达基因P23基因并进行生物信息学分析, 为进一步研究该基因的功能以及凡纳滨对虾的分子选育等研究提供信息。以凡纳滨对虾雌虾极端体重个体腹部肌肉为实验材料, 利用抑制消减杂交(SSH)技术构建极大体重雌性个体和极小体重雌性个体腹部肌肉组织正反向消减cDNA文库:正库(以极大体重个体为试验组, 以极小体重个体为驱动组, L-S)和反库(以极小体重个体为试验组, 以极大体重个体为驱动组, S-L)消减cDNA文库, 并采用实时定量技术分析P23基因的组织表达规律, 利用生物信息学对其功能和结构进行预测。以β-actin为看家基因检测两个文库的消减效率分别为210和25, 实时定量技术分析结果表明P23基因在体重的调节中起上调作用。P23基因编码区序列全长495bp, 编码165个氨基酸, GenBank登录号:JF806619。生物信息学分析发现P23蛋白部分序列含有强疏水性, 无跨膜螺旋结构, 两种信号肽预测都显示P23含有信号肽。     

An Improved Time Domain Approach for Analysis of Floating Bridges Based on Dynamic Finite Element Method and State-Space Model

The floating bridge bears the dead weight and live load with buoyancy, and has wide application prospect in deep-water transportation infrastructure. The structural analysis of floating bridge is challenging due to the complicated fluid-solid coupling effects of wind and wave. In this research, a novel time domain approach combining dynamic finite element method and state-space model (SSM) is established for the refined analysis of floating bridges. The dynamic coupled effects induced by wave excitation load, radiation load and buffeting load are carefully simulated. High-precision fitted SSMs for pontoons are established to enhance the calculation efficiency of hydrodynamic radiation forces in time domain. The dispersion relation is also introduced in the analysis model to appropriately consider the phase differences of wave loads on pontoons. The proposed approach is then employed to simulate the dynamic responses of a scaled floating bridge model which has been tested under real wind and wave loads in laboratory. The numerical results are found to agree well with the test data regarding the structural responses of floating bridge under the considered environmental conditions. The proposed time domain approach is considered to be accurate and effective in simulating the structural behaviors of floating bridge under typical environmental conditions.