Zn-Al合金镀层低铬钝化膜的组成和耐蚀性

目前，在中国采用热浸镀Zn及其合金一直是防止钢材在自然环境中腐蚀的最经济有效的方法，为了提高镀层的防腐和涂装性能，往往在其表面进行钝化处理。传统的镀锌层钝化处理工艺均采用高浓度的铬酸盐溶液， 这对环境污染和人体的危害较严重。随着环境保护问题日益引起人们的重视，在传统的高铬钝化基础上，低浓度铬酸盐钝化开始步入实用性阶段(吴双成，1996；卢燕平等，1995)。但是，目前低铬钝化研究主要集中于热浸镀Zn或电镀Zn镀层，而合金镀层由于化学稳定性高，与铬酸溶液自发反应能力差，无法采用常规的低铬钝化方法处理，有关这方面的报道目前尚少。王洪仁(1998)对Zn-Al合金镀层的低铬钝化处理进行了有益的探索，获得了一个优化的低铬钝化配方和稳定的钝化工艺，并成功地应用于热浸镀Zn-Al合金镀层的表面防锈处理；实验证明，海水在模拟浸泡6个月后，钝化处理Zn-Al合金镀层的腐蚀失重比未钝化样品降低65.9%，表明低铬酸盐钝化使Zn-Al合金镀层的耐海水腐蚀性能得到显著提高(Li Y et al.，2001)。本文作者在前人基础上对Zn-Al合金镀层低铬钝化膜的组成和耐盐雾腐蚀性进行了研究，并初步探讨了钝化膜的形成过程及其耐蚀机理。对Zn-Al合金镀层低铬钝化处理技术的研究，不仅大大降低了对环境的污染和人体的危害，也是在低铬钝化研究方面的重大突破，具有十分重要的意义和实际应用价值。     

烃源岩中有机黏粒复合体——天然的生烃母质

传统观点认为从烃源岩中分离出的干酪根是油气生成的母质,但它的处理方式破坏了有机质与矿物的原始赋存状态。为此,选取济阳坳陷埋深280～3 900m烃源岩,提取<2μm的有机黏粒复合体,研究其结构和生烃特征。有机黏粒复合体主要由蒙皂石和伊利石组成,TOC为2.62%～9.78%,经H2O2处理后TOC仍高达1.23%～4.63%,表明烃源岩中有机质主要富集在有机黏粒复合体中。有机黏粒复合体加热到250℃时,在XRD曲线上的衍射峰(d001)在1.3～1.4nm;加热至550℃时,衍射峰(d001)才移至1.0nm处;并且在DTA曲线上350℃附近的放热峰极其稳定,这些特征表明有机质进入到黏土矿物层间域。在PY-GC(热解—色谱)曲线上,烃源岩和有机黏粒复合体都在250～550℃释放C20—C30的有机组分,并在450℃释放量达到峰值。由此可见,烃源岩中的有机黏粒复合体,是烃源岩中有机质富集的主体,具有较好的稳定性,并释放出与原油特征相似的有机组分,表明它是具有巨大潜力的天然的生烃母质。     

Zn-Al合金镀层低铬钝化膜的组成和耐蚀性

目前,在中国采用热浸镀Zn及其合金一直是防止钢材在自然环境中腐蚀的最经济有效的方法,为了提高镀层的防腐和涂装性能,往往在其表面进行钝化处理。传统的镀锌层钝化处理工艺均采用高浓度的铬酸盐溶液,这对环境污染和人体的危害较严重。随着环境保护问题日益引起人们的重视,在传统的高铬钝化基础上,低浓度铬酸盐钝化开始步入实用性阶段(吴双成,1996;卢燕平等,1995)。但是,目前低铬钝化研究主要集中于热浸镀Zn或电镀Zn镀层,而合金镀层由于化学稳定性高,与铬酸溶液自发反应能力差,无法采用常规的低铬钝化方法处理,有关这方面的报道目前尚少。…     

氨基多糖多孔微球载体制备及其脲酶固定化特性

以脱乙酰度为 95 % ,分子量分别为 98KDa和 1 1 30 KDa的氨基多糖为载体材料 ,采用三聚磷酸钠固定的方法制成氨基多糖微球 ,并以此氨基多糖微球为载体用戊二醛交联法进行脲酶固定化研究。结果表明 :在 3%复合氨基多糖溶液中大、小分子量氨基多糖质量比为 1∶ 5时微球载体机械强度较好 ,表面光滑。用 Ca CO3 (w/w=1 /1 )处理则可得到表面具有蜂窝状结构的多孔微球载体 ;光滑表面微球载体与多孔微球载体对脲酶的固定化效率分别是 5 1 .5 %和 6 8% ;用 1 .5 cm× 1 5 cm柱进行尿素转化时间 1 2 min,光滑表面微球载体固定化脲酶和多孔微球载体固定化脲酶对尿素溶液(30 0 mg/L)转化率分别为 91 .8%和 99.99%。这一结果说明 ,利用多孔微球载体可有效地提高载体对脲酶的固定化效率 ,并且能彻底的分解尿素 ,提高尿素转化率     

孤立波与直墙式多孔介质结构相互作用数值分析

以连续性方程和雷诺平均方程为控制方程,用k-ε模型封闭方程组,采用VOF方法追踪自由面,建立了具有造波和消波功能的二维孤立波数值水槽。并基于改进的Darcy多孔介质模型研究了二维孤立波与直墙式多孔介质结构的相互作用问题。数值分析了孤立波与直墙式多孔结构相互作用引起的流场和波形变化特性,并与文献中的实验结果进行了比较,数值结果与实验结果吻合良好。     

南黄海和东海陆架区束毛藻(Trichodesmium)的分布特征

本文根据国家海洋局1977年12月至1978年11月在28°-34°N,120°30'-127°E海域69个站逐月用小型浮游生物网(孔径64μm)自底至表垂直拖曳的805份样品,研究束毛藻(Trichodesmium)周年的分布特征,并探讨其与若干环境因子(温、盐度和黑潮等流系等)的关系。     

不同气氛下多孔硅中电子偶素湮没行为研究

使用正电子湮没谱学方法,在不同气氛下对电化学腐蚀法制备的多孔硅中电子偶素的湮没行为进行了系统的研究.正电子湮没寿命谱测试结果表明,样品中存在长达40 ns的电子偶素湮没成分,并且进入多孔硅膜层的正电子约有80%形成电子偶素,具有非常高的电子偶素产额;在氧气气氛下,由于气体导致o-Ps发生自旋转化猝灭是使多孔硅样品中电子偶素寿命缩短的主要原因.结合正电子寿命-动量关联谱测量结果,分析了不同气氛下多孔硅样品中电子偶素湮没寿命及动量变化关系,讨论了多孔硅中电子偶素的湮没机理以及气氛对孔径计算理论模型的影响.     

东山湾表层沉积物中几种化学成分的分布特征

东山湾位于福建省的南部,即23°40′—23°57′N;117°25′—117°37′E。湾内水深介于0—31米之间(经潮流订正)。湾的西北面有漳江河水流入,年径流量约为4.675亿立方米。由于河水带入大量的有机质和营养物质,使沉积物中有机碳和全氮的丰度较大。有关东山湾沉积地球化学的研究,目前报道不多。我们于1982年采集了表层沉积物样品52个(图1),分析了其有机碳、碳酸盐、全氮和可溶性硅酸盐的含量,探讨了各要素的主要分布特征,初步讨论了它们之间以及它们与粒径和沉积类型的关系。     

超声波和加热处理对三疣梭子蟹肝胰腺丝氨酸蛋白酶的影响

以三疣梭子蟹(Portunus trituberculatus)肝胰腺中丝氨酸蛋白酶为研究对象,对其进行超声波和加热处理,通过紫外光谱、荧光光谱分析和蛋白质变性凝胶电泳分析丝氨酸蛋白酶的变化。研究表明,超声功率和超声时间对丝氨酸蛋白酶的酶活有不同影响。低功率短时间超声处理会使酶活力升高,随着功率和超声时间的增加,酶活力逐渐降低。紫外光谱显示,超声处理使酶液紫外吸收出现蓝移现象,而加热对其影响不大。内源荧光显示,超声和加热处理均对蛋白酶有荧光猝灭作用。SDS-PAGE显示,超声和加热2种处理方法均能引起丝氨酸蛋白酶不同程度的降解。     

一维综合孔径微波辐射计遥感海面温度的敏感性分析

一维综合孔径微波辐射计能够有效提高观测的空间分辨率，其观测入射角通常在0°~55°范围内变化。为了开发适用于一维综合孔径微波辐射计的海面温度反演算法，需要评估其观测亮温对海洋大气环境要素的敏感性。利用海面发射率模型和大气辐射传输模型，构建了适用于一维综合孔径微波辐射计的微波海洋大气辐射传输模式，研究了C波段垂直和水平极化微波辐射亮温在不同入射角下对海洋大气环境要素的敏感性变化情况，并定量计算了相应的敏感系数。结果表明:垂直和水平极化亮温对海洋大气环境要素的敏感性表现出不同的特性。随着入射角的增大，垂直极化亮温对海面温度的敏感性增强，对海面风场的敏感性相对减弱；水平极化亮温则相反。由大气水汽含量和云液态水含量误差引入的垂直和水平极化亮温误差随入射角增大而增大，但是，即使在55°的大入射角下垂直和水平极化亮温误差仍小于0.12 K。对于海面温度反演精度优于1 K的要求，一维综合孔径微波辐射计的测温精度需优于0.6 K。研究结果对于一维综合孔径微波辐射计海面温度反演算法的研究和载荷设计具有一定的理论指导意义。     

Laboratory modeling of the structure of a thermal bar and related circulation in a basin with a sloping bottom

Development of a thermal bar in a laboratory flume with an inclined bottom (3.7°–12°) under the conditions of cooling/heating of the water with a temperature close to that of the maximal density is studied. The structure of the temperature field and currents during different stages of the circulation is examined: (i) formation of an along-slope gravity current, (ii) generation of a subsurface jet, and (iii) transformation of one type of the circulation into another at passing the temperature of the maximum density. The “fall” and “spring” types of the thermal bar are shown to be dynamically equivalent: the transport of the near-shore waters to the deepwater part, which is driven by the buoyancy flux rather than by the heat flux across the surface, transforms stage (i) into stage (ii), while the opposite (on-shore) flow is generated in the intermediate layers. A comparison of the results with the field and laboratory data published allows us to suggest that the propagation of the thermal bar front in the “fast” stage can be considered as the development of a convective jet with its velocity U ～ h ^3/4, which is proportional to the growing thickness of the upper layer h affected by the heating/cooling processes     

Some seasonal water temperature patterns in the Hauraki gulf,New Zealand

The changing pattern of water temperature in the Hauraki Gulf at approximately two‐monthly intervals during one and one‐half seasonal cycles in 1965–66 was determined from sea surface temperatures and bathythermograph profiles.

Surface and bottom temperatures ranged from 22.0°c and 20.5°c respectively in March to 12.5°c and 13.0°c in July‐September. Seasonal temperature ranges and short‐term variations were greatest in the shallow south‐west Gulf.

In winter the Gulf water was coolest close to shore. It was typically isothermal in depth but a temperature inversion of approximately l°c frequently formed, probably because of the combination of strong winds and an increased outflow of cool, low salinity water from harbours and bays. A similar inversion in Colville Channel may have been caused by more complex tidal and/or ocean current conditions.

In spring and summer the Gulf became thermally stratified, with warmest temperatures in the shallow areas. Thermoclines were generally irregular in position and size, and probably represented solar heating and minor current boundaries rather than a distinct separation of major water masses. In late summer and autumn bottom temperatures increased and almost equalled the maximum surface temperature.

During autumn surface water temperatures close to land decreased rapidly to return the Gulf to its winter isothermal condition.

Local factors (wind, rainfall, tides, depth of water, and proximity to land) probably influence sea temperatures in the Gulf. Seawards of a line from Cape Rodney to Cape Colville oceanic conditions prevail; water temperatures are more constant and increase to seaward in both winter and summer.

Oceanic and Gulf waters meet and mix in the Rodney‐Colville area, and Gulf water is transported east through Colville Channel. The extent of oceanic water penetration into the Gulf at depth is unknown.     

南海暖水的季节变化特征及数值模拟

根据Ｌｅｖｉｔｕｓ资料,对具有立体结构的南海暖水给出了定义,分析发现：南海暖水的季节变化过程可分为发展、维持、退缩和消失４个阶段;就气候平均而言,南海暖水在季节变化中始终保持西北部浅、东南部深的特点;南海暖水的深度与同期温跃层上界的深度在空间分布特征与季节变化趋势上都基本类似。采用“ｉｎｔｅｒｍｅｄｉａｔｅ”模式模拟了南海暖水的范围和厚度,结果表明发展阶段的南海暖水范围和厚度的增长主要是因为南海地     

Hydroelastic Response of VLFS with An Attached Submerged Horizontal Solid/Porous Plate Under Wave Action

The hydroelastic responses of a submerged horizontal solid/porous plate attached at the front of a very large rectangular floating structure(VLFS) under wave action has been investigated in the context of linear water wave theory. Darcy's law is adopted to represent energy dissipation in pores. It is assumed that the porous plates are made of material with very fine pores so that the normal velocity across the perforated porous is linearly associated with the pressure drop. In the analytic method, the eigenfunction expansion-matching method(EEMM) for multiple domains is applied to solve the hydrodynamic problem and the elastic equation of motion is solved by the modal expansion method. The performance of the proposed submerged horizontal solid/porous plate can be significantly enhanced by selecting optimal design parameters, such as plate length, horizontal position, submerged depth and porosity. It is concluded that good damping effect can be achieved through installation of solid and porous plate.Porous plate has better damping effect at low frequencies, while solid plate has better damping effect at high frequencies. The optimal ratio of plate length to water depth is 0.25-0.375, and the optimal ratio of submerged depth to water depth is 0.09-0.181.     

Convection induced by cooling at one side wall in two-dimensional non-rotating fluid —applicability to the deep Pacific circulation—

In recognition that similarity in the density balance leads to resemblance in circulation between the two-dimensional non-rotating and three-dimensional rotating systems which have similar density stratification, we investigate convection induced by cooling at one side wall and heating at the sea surface by using a two-dimensional non-rotating model as idealized representation for the deep Pacific circulation. In the model, various vertical profiles are taken for the side wall cooling, which are assumed to correspond to the density structure of the Anatarctic Circumpolar Current. In a small diffusivity range, two important features are found to be robust against change in the vertical profile of the side wall cooling. One is that the density stratification is horizontally almost uniform. The other is that the balance in the density equation between the vertical advection and the vertical diffusion holds in the interior. Consequently, the vertical density balance, together with the equation of continuity, determines the circulation pattern for the prescribed vertical profile of the side wall cooling. The multi-layered meridional flow, which is expected to exist in the deep Pacific, is shown to form for certain vertical profiles of the side wall cooling.     

Coastal upwelling along the north coast of Papua New Guinea and SST cooling over the pacific warm pool: A case study for the 2002/03 El Niño event

We investigate an overlooked mechanism—coastal upwelling—for sea surface temperature (SST) cooling in the western side of the mean location of the Pacific warm pool (WSWP: 5°S–5°N, 140°E–150°E) prior to El Niño onset. We analyze various observed data such as the TRIangle Trans-Ocean buoy Network (TRITON) moored buoy data, Conductivity-Temperature-Depth (CTD) data, satellite data and a hindcast experiment output by a high-resolution ocean general circulation model (OGCM). We focus on the precondition of the 2002/03 El Niño event, for which many datasets are available. Relatively cool water upwelled along the north coast of Papua New Guinea (PNG) during December 2001, prior to the onset of the 2002/03 El Niño event, and then spread out over a wider area to the northeast. Simultaneously, strong west-northerly surface winds occur along the north coast. Heat budget analysis of TRITON buoy data in the WSWP reveals that negative zonal heat advection due to eastward current is the main factor for cooling the mixed layer in the WSWP in contrast to the warming effect of the surface heat flux during the period. This cooling requires a source of colder water to the west. Similar analysis of OGCM outputs also suggests that the upwelled relatively cool water along the PNG north coast, and its northeastward extension to the equatorial region, contributes to cooling of the surface water over the WSWP mainly via negative zonal heat advection. Similar mechanisms are confirmed also for the 1982/83 and 1997/98 El Niño events by analyses of OGCM outputs and historical SST data. The low SST in the WSWP generated a positive zonal SST gradient together with high SST east of the WSWP. It may contribute to enhancement of the westerly surface wind in this region, leading to the onset of the 2002/03 El Niño event.     

A coupled numerical model for simulation of wave breaking and hydraulic performances of a composite seawall

A numerical model is developed by combining a porous flow model and a two-phase flow model to simulate wave transformation in porous structure and hydraulic performances of a composite type low-crest seawall. The structure consists of a wide submerged reef, a porous terrace at the top and an impermeable rear wall. The porous flow model is based on the extended Navier-Stokes equations for wave motion in porous media and k−ε turbulence equations. The two-phase flow model combines the water domain with the air zone of finite thickness above water surface. A unique solution domain is established by satisfying kinematic boundary condition at the interface of air and water. The free surface advection of water wave is modeled by the volume of fluid method with newly developed fluid advection algorithm. Comparison of computed and measured wave properties shows reasonably good agreement. The influence of terrace width and structure porosity is investigated based on numerical results. It is concluded that there exist optimum value of terrace width and porosity that can maximize hydraulic performances. The velocity distributions inside and in front of the structure are also investigated.     

强流脉冲电子束作用下金属纯Cu的微观结构状态——空位簇缺陷及表面微孔结构

利用强流脉冲(HCPEB)电子束技术对多晶纯Cu进行了辐照处理,并利用透射电镜对HCPEB诱发的空位簇缺陷进行了表征.实验结果表明,HCPEP辐照金属可在纯Cu表层诱发大量的过饱和空位,并形成四方形空位胞及空位型位错圈和堆垛层错四面体(SFT),HCPEB瞬间的加热和冷却诱发的幅值极大的应力和极高的应变导致的整个原子平面的位移是空位簇缺陷形成的主要原因.此外,扫描电镜分析表明HCPEB辐照可以在纯Cu表面形成高密度、弥散分布和尺寸细小的微孔.过饱和空位或空位团簇沿晶体缺陷向表面扩散、凝聚是表面微孔形成的根     

海底接驳盒装置的散热结构设计及其热分析

针对海底接驳盒装置的散热方式及结构进行了研究探讨.基于热传导散热机理,设计了一种圆柱内壁面结合螺杆顶紧的散热结构,使接驳盒装置的散热效率有所提高.针对所设计的散热结构进行了不同温度下不同发热功率下的仿真实验,得到了相对应的最高温度曲线.还进行了水箱接驳盒装置的散热实验,与所得有限元仿真数据进行了横向对比,进一步确定了所设计散热结构的合理性.     

波浪与多孔介质结构相互作用SPH模拟

应用经CSPM法和黎曼解修正后的光滑粒子流体动力学(SPH)方法,建立了主动吸收无反射数值波浪水槽,研究波浪作用下多孔介质结构的水动力特性。流体运动控制方程采用N-S方程,多孔渗水结构内流体的运动控制方程考虑渗流力的影响。数值计算结果给出了水槽内不同位置测点的波面历时曲线和越浪量随时间变化曲线,并同试验结果和Philip Liu的数值计算结果进行了比较。并对一个波浪周期内斜坡堤多孔介质结构内外的速度场和压力分布进行了讨论分析。计算分析表明,数值计算波面较Philip Liu的计算结果与试验结果吻合更好。说明应用SPH方法建立的二维数学模型能够较好地模拟破碎波在多孔渗水斜坡上的爬坡和越浪。