冲击作用下水力驱动装置流固耦合动力学

研究反应堆控制棒水力驱动装置在冲击作用下的流固耦合动力学问题。针对系统受向上和向下冲击两种情况,以及系统不同的设计参数,采用商用软件MSC.DYTRAN计算了系统计算模型的动力学响应。计算结果表明水力驱动装置在冲击载荷下的响应与冲击方向、步进缸水柱长短有关。向下冲击比向上冲击使系统产生更大的响应;在同样的冲击下,步进缸水柱越长响应幅值越大。此分析结果可用来评估系统的抗冲击能力。     

核反应堆控制棒水压驱动技术

介绍了控制棒水压驱动系统的技术方案、工作原理、技术效果和安全特性。在对清华大学发明的水力驱动控制棒系统深入研究的基础上,结合商用压水堆磁力提升器的优点,开发一种新型内置式控制棒驱动技术。该驱动技术解决了磁力提升器把驱动机构置于核反应堆压力壳外的缺点,但保留了抓式机构驱动的优点;解决了水力驱动控制棒系统动压驱动因工况变化而引起的驱动特性的复杂性的缺点,继承了内置式控制棒驱动机构不贯穿压力壳、传动线短、避免了弹棒事故等优点。该驱动技术主要应用于一体化布置核反应堆,可以推广到其他研究堆。     

水力步进缸系统动态保持特性研究

水力步进缸系统是以流体动压为动力的反应堆新型控制棒驱动装置。本文将整个水力步进缸系统纳入分析,提出了系统的非恒定流模型,并用这种模型对水力步进缸系统的动态保持特性进行了理论研究和实验验证,理论研究结果与实验结果较好的吻合,验证了计算模型建立的合理性,本文从理论上论证了水力步进缸系统在保持态具有“水力自锁”特性,计算出了系统的固有频率。     

控制棒水力驱动系统在摇摆工况下的运行特性

通过由控制棒水力驱动系统实验本体、六自由度船舶运动模拟器及测量与控制系统组成的实验装置，进行了实验本体随模拟器摇摆时控制棒的步升、步降及全程快速落棒实验，还进行了实验本体横倾４５°静态下的快速落棒实验，取得了一系列实验数据。实验结果表明：控制棒水力驱动系统在摇摆角达３５°，周期为１０ｓ时仍具有良好的运行可靠性和固有安全性；在横倾４５°时仍能靠重力顺利落棒。因而该系统经过适当改进后可以满足摇摆工况下要求，为该系统应用于船用核动力堆提供了实验依据。     

水力驱动控制棒热态极限落棒能力分析

控制棒驱动机构是核反应堆的关键设备,其是否正常运行直接关系到核反应堆的安全性。该文对水力驱动控制棒系统在摩擦力卡棒和倒置等极限工况下的停堆问题,提出了步进缸内腔卸压的解决方法,并在热态实验研究的基础上,建立了正置落棒和倒置插棒的理论模型。分析了极限落棒过程参数(位移、速度和棒内外差压)的变化规律,得到了摩擦力卡棒和倒置等极限工况下控制棒插入堆芯的能力。结果表明:在极限工况下水力驱动控制棒有足够能力插入堆芯。     

反渗透海水淡化系统故障分析

在对反渗透海水淡化系统工艺、机理研究和分析的基础上,利用故障树分析法,绘制了以"脱盐率下降且产水量上升"为顶事件的反渗透海水淡化系统故障树,利用布尔代数将故障树进行化简,求出最小割集及最小径集。对最小割集与最小径集给以结构重要度分析,从而得出导致故障发生的原因并以重要度进行排序,给出维护及预防建议,增加了系统的安全程度。该方案可以对反渗透海水淡化工作提供借鉴。     

不同流速下电磁驱动控制棒的落棒特性

控制棒的落棒在反应堆控制中是一个十分重要的方面,尤其是落棒时间这个参数。因此,进行了可移动线圈电磁驱动控制棒机构在不同流速下的快速落棒实验;用VC编写的软件控制了实验过程并记录了实验数据;分析了快速落棒实验的数据;得到了各种工况的落棒时间,此外还分析了造成落棒时间差异的原因。结果表明:在额定工况下,落棒时间小于1s;可移动线圈电磁驱动机构的快速落棒性能完全符合研究堆运行的设计要求。     

一种设有冷凝壁的海水淡化装置

淡水资源的有限性、用水需求的上升性决定了淡水资源问题是目前亟需解决的难题,通过制作高效的海水淡化装置制取淡水对当今世界发展是至关重要的。该研究在海水淡化产业普遍采用的蒸馏法的基础上,设计了一种新型海水淡化装置。该装置分为3个部分:蒸馏部分、冷凝部分和自动控制部分。该装置的创新特色体现在对冷凝壁和蒸馏室进行改进提高液滴的收集效率的同时,对废弃物进行充分利用,且可以满足不同使用者的需求,具有广阔的应用空间。     

太阳能海水淡化蒸馏器的传热实验研究

利用科研项目设计制造的太阳能海水淡化装置进行实验教学,由学生完成太阳能热水系统的测试,海水淡化蒸馏系统的运行,并进行实验数据整理和分析,得出实验结论.     

5MW供热堆控制棒水力驱动系统

５ ＭＷ供热堆使用水力步进式驱动系统作为控制棒驱动系统．它是一种不同于压水堆使用的电磁－机械式传动的一种全新的控制棒传动。它以反应堆冷却剂（水）为工作介质，经泵加压后，注入安装在压力壳内的水力步进缸。通过由电磁阀组成的控制单元，控制注入步进缸的流量，使缸外套作步进运动，拖动中子吸收元件；控制核反应的进行。整个系统包括有１３套传动缸及其控制单元，所有的控制单元集成到两个组合阀体上。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the