野生与豢养长江江豚血清氨基酸含量比较

应用高效液相色谱(HPLC)技术,首次测定了湖北石首长江天鹅州白豚自然保护区野生长江江豚(Neopho-caena phocaenoides asiaeorientalis)和中国科学院水生生物研究所白豚馆人工饲养的长江江豚血清中17种氨基酸的含量。结果表明,除了脯氨酸Pro、蛋氨酸Met和组氨酸His外,人工饲养江豚血清中其余14种氨基酸(天门冬氨酸Asp、谷氨酸Glu、丝氨酸Ser、精氨酸Arg、甘氨酸Gly、苏氨酸Thr、丙氨酸Ala、异亮氨酸Ile、亮氨酸Leu、苯丙氨酸Phe、缬氨酸Val、赖氨

Hybrid passive/active inertial actuators to attenuate the structural response of a submerged hull

This paper theoretically investigates the application of tuned vibration absorbers and hybrid passive/active inertial actuators to reduce the vibrational responses of plates and shells. The passive/active actuators are initially applied to a simple plate. A model of a submerged hull consisting of a ring stiffened finite cylinder with bulkheads and external fluid loading is then considered. The fluctuating forces from the propeller result in excitation of the low frequency global hull modes. Inertial actuators and tuned vibration absorbers are located at each end of the hull and in circumferential arrays to reduce the hull structural response at its axial resonances. The control performance of the hybrid passive/active inertial actuator, where the passive component is tuned to a structural resonance, is compared to the attenuation achieved by a fully passive tuned vibration absorber. This work shows the potential of using hybrid passive/active inertial actuators to attenuate the global structural responses of a submerged vessel.

集胞藻PCC6803 priA基因的突变体

中国科学院知识创新工程重要方向项目(KSCX2-SW-332)

集胞藻PCC6803铜离子诱导表达平台的构建

在集胞藻PCC6803中,基因敲除是研究基因功能的最直接有效的方法,但是对于某些生存必需的基因则无法通过这种方法获得突变株。为研究集胞藻PCC6803中此类基因的功能,在其基因组中构建了一个petE基因启动子(PpetE)控制的铜离子诱导表达的平台。将集胞藻PpetE装配在lacZ报告基因的上游,通过同源双交换整合到这种蓝藻的基因组中。通过调节培养基中铜离子的浓度发现,lacZ的表达能够人为控制。特别是当铜离子浓度在6—400nmol/L范围时,LacZ活力随铜离子浓度增加呈S型增长关系。利用这个铜离子诱

人工藻结皮对库布齐沙地土壤酶活性的影响

土壤酶是土壤内存在的具有生物活性的蛋白质,土壤是土壤酶的良好介质,为各种酶类提供酶促条件,且土壤成分与酶通过共价键、离子键或氢键等方式的吸附结合作用,能防止酶的钝化失活。目前已发现的土壤酶约60种,主要来自于土壤微生物,土壤酶的主要作用是参与C、N、P、S等重要营养元素的循环,在植物营养物质的转化中起着重要作用,它与土壤微生物一起共同推动土壤生物化学的全过程,土壤酶活性作为土壤质量的生物活性指标已被广泛接受。我国对土壤酶的研究始于20世纪60年代,20世纪80年代后,随着环境科学的发展,土壤酶研究越来越受

母鸡输卵管子宫部初级感觉神经元的CB-HRP法定位研究

应用CB-HRP溶液注入母鸡输卵管子宫部浆膜下,四甲基联苯胺(TMB)组织化学呈色,以探察母鸡输卵管子宫部初级感觉神经元的定位。结果表明:母鸡输卵管子宫部的初级感觉神经元位于双侧T1-LS13脊神经节、颈静脉神经节和结状神经节。标记细胞数分布不均,在体左侧多于体右侧,在脊神经节多于颈静脉神经节和结状神经节。在脊神经节内标记细胞有T5-LS1和LS8-LS11前后两个相对集中区,峰值分别在T7和LS11。说明尽管母鸡输卵管子宫部是单侧发育成熟脏器,但其感觉沿双侧脊神经和迷走神经传入中枢,以体左侧传入为主;且

鳜IL-1β基因的克隆及原核表达

用RACE PCR获得了鳜白介素-1β(IL-1β)的全长cDNA.鳜IL-1β的cDNA全长为1298 nt(核苷酸),其5′非编码区包含UTR 93 nt;3′非编码区包含452 nt;其开放阅读框内包含753 nt,翻译成251个氨基酸.将鳜IL-1β克隆到原核表达载体pET-32a上,在大肠杆菌Rosetta- gami(DE3)内以包涵体形式得以高效表达.

不同培养基对发菜细胞生长和光合活性的影响

研究测定了发菜(NostocflagelliformeBorn.etFlah.)细胞在不同培养基中的生长速率、光合作用和叶绿素荧光活性。结果显示培养11d后:Detmer培养基中叶绿素a的含量为1.08mg/L,Kratz-Myers培养基中叶绿素a的含量为1.87mg/L,水生104号培养基中叶绿素a的含量为1.21mg/L,BG11培养基中叶绿素a的含量为2.18mg/L,表明在BG11培养基中培养的细胞具有最高生长速率;与另外4种不同浓度的BG11培养基相比,上述BG11培养基培养的发菜具有最大的光

三氯杀螨醇对大型溞的毒性和环境雌激素效应

中国科学院知识创新工程重大项目(KZCX1 SW 12 ) ; 国家重大环境课题“滇池蓝藻水华污染控制技术研究”(K99 0 5 3 5 0 1); 973项目(2 2 0 2CB412 3 0 0 ); 中国科学院方向性创新课题(2 2 0 3 16)资助

The vibro-acoustic analysis of built-up systems using a hybrid method with parametric and non-parametric uncertainties

An existing hybrid finite element (FE)/statistical energy analysis (SEA) approach to the analysis of the mid- and high frequency vibrations of a complex built-up system is extended here to a wider class of uncertainty modeling. In the original approach, the constituent parts of the system are considered to be either deterministic, and modeled using FE, or highly random, and modeled using SEA. A non-parametric model of randomness is employed in the SEA components, based on diffuse wave theory and the Gaussian Orthogonal Ensemble (GOE), and this enables the mean and variance of second order quantities such as vibrational energy and response cross-spectra to be predicted. In the present work the assumption that the FE components are deterministic is relaxed by the introduction of a parametric model of uncertainty in these components. The parametric uncertainty may be modeled either probabilistically, or by using a non-probabilistic approach such as interval analysis, and it is shown how these descriptions can be combined with the non-parametric uncertainty in the SEA subsystems to yield an overall assessment of the performance of the system. The method is illustrated by application to an example built-up plate system which has random properties, and benchmark comparisons are made with full Monte Carlo simulations. © 2012 Elsevier Ltd. All rights reserved.

武汉东湖沉积物中酸挥发性硫化物(AVS)的深度分布及其影响因素

沉积物中酸挥发性硫化物(AVS)是硫化物的生成、氧化和扩散等综合作用的反映,有机物的供给、硫酸盐的还原等因素都能影响其分布特征. 本文对武汉东湖三个污染程度不同站点的AVS深度分布特征进行了研究,结果表明,AVS含量在一定深度沉积物中具有最大值,东湖沉积物中AVS的深度分布具有两种不同的模式,I站和II站AVS浓度峰在5cm左右的表层沉积物中,且AVS还原层深度较狭窄,而III站AVS浓度峰处于10-20cm深度范围,沉积物中有机质负荷的差异是导致这种分布特征的重要原因. 沉积物中有机质含量对AVS的深度

An efficient model for the dynamic behaviour of a single pile in viscoelastic soil

This paper presents a novel, three-dimensional, single-pile model, formulated in the wavenumber domain and adapted to account for boundary conditions using the superposition of loading cases. The pile is modelled as a column in axial vibration, and a Euler-Bernoulli beam in lateral vibration. The surrounding soil is treated as a viscoelastic continuum. The response of the pile is presented in terms of the stiffness and damping coefficients, and also the magnitude and phase of the pile-head frequency-response function. Comparison with existing models shows that excellent agreement is observed between this model, a boundary-element formulation, and an elastic-continuum-type formulation. This three-dimensional model has an accuracy equivalent to a 3D boundary-element model, and a runtime similar to a 2D plane-strain analytical model. Analysis of the response of the single pile illustrates a difference in axial and lateral vibration behaviour; the displacement along the pile is relatively invariant under axial loads, but in lateral vibration the pile exhibits localised deformations. This implies that a plane-strain assumption is valid for axial loadings and only at higher frequencies for lateral loadings. © 2013 Elsevier Ltd.

On the applicability of the lognormal distribution in random dynamical systems

This paper is concerned with the probability density function of the energy of a random dynamical system subjected to harmonic excitation. It is shown that if the natural frequencies and mode shapes of the system conform to the Gaussian Orthogonal Ensemble, then under common types of loading the distribution of the energy of the response is approximately lognormal, providing the modal overlap factor is high (typically greater than two). In contrast, it is shown that the response of a system with Poisson natural frequencies is not approximately lognormal. Numerical simulations are conducted on a plate system to validate the theoretical findings and good agreement is obtained. Simulations are also conducted on a system made from two plates connected with rotational springs to demonstrate that the theoretical findings can be extended to a built-up system. The work provides a theoretical justification of the commonly used empirical practice of assuming that the energy response of a random system is lognormal.

Magnetocaloric effect in La0.75Sr0.25MnO3 manganite

The polycrystalline manganite La0.75Sr0.25MnO 3 prepared by an alternative carbonate precipitation route reveals the rhombohedral perovskite structure. Magnetization isotherms measured up to 2 T are used to determine Curie temperature of 332 K by means of Arrott plot. Maximum of magnetic entropy change is found at Curie temperature. The relative cooling power equal to 64 J/kg for 1.5 T magnetic field, is superior as compared to the manganite with the same chemical composition from the solgel method. © 2010 Elsevier B.V. All rights reserved.