双基推进剂结构对爆炸性能的影响

为研究不同装药结构的爆速及其对钢板的破坏影响,以外径为45.5 mm、内径为8.2 mm、密度为1.61 g/cm3的双基推进剂单孔药柱为研究对象,在推进剂结构中设置不同单元药柱长度、不同单元药柱间隙长度,在间隙中有无填充氧化剂弹性体。通过爆速测试和见证板方法得到:在充填间隙后,装药结构完全爆轰,爆速范围为6.7~7.25 km/s;在间隙无充填时,随着间隙长度的增加,爆炸性能下降,在单元药柱长度低于50 mm且间隙长度大于3 mm后不能爆轰。测试得到了单元药柱长80 mm,间隙为5 mm装药结构的爆速为1.9 km/s,并用见证板和高速摄影手段进行了验证。     

改性双基推进剂药柱表面静动态应变测量方法

针对推进剂药柱材料线胀系数大、应变大,传统的电测技术测量其表面应变时死片率高的问题,该文采用近似将应变片植入推进剂装药的粘贴技术,建立了一种改进的测量改性双基推进剂药柱表面应变的电测法。应用该法测量了单孔推进剂药柱在静载荷和冲击载荷作用下的应变响应过程,分析了推进剂材料的延滞回复现象。结果表明:该方法可以准确地测量药柱的的静态、准静态及动态应变等粘弹性力学特征,适于固体火箭发动机推进剂药柱的结构完整性研究。     

DNP/HMX熔铸炸药成型工艺研究

3，4-二硝基吡唑（DNP）在能量密度、安定性等方面性能优异，是具有广阔应用前景的新型熔铸炸药载体. 为研究DNP基熔铸炸药装药工艺和成型规律，以DNP/HMX（40/60）熔铸炸药为实验配方，采用数值模拟与实验验证相结合的方法，研究冒口预热工艺对DNP/HMX熔铸炸药装药冷却凝固时间与装药缺陷的影响规律，并在此基础上通过数值模拟方法研究大尺寸DNP/HMX熔铸炸药成型工艺. 结果表明:冒口预热工艺能够改变装药内部凝固顺序，保证补缩通道持续畅通，从而有效减少药柱内缩松产生；装药尺寸对炸药成型过程影响显著:随着装药尺寸增加，相同工艺条件下药柱冷却耗时大幅延长，缩松占比明显上升，需要更高冒口预热温度消除药柱内缩松；尺寸超过临界值后，仅靠冒口预热工艺已无法消除药柱内部缩松.      

工艺溶剂对AP/CMDB推进剂燃烧性能的影响

通过溶剂含量的测定,研究了AP/CMDB推进剂药柱工艺溶剂含量的分布规律,测试了不同工艺溶剂含量推进剂的燃速,采用单幅摄像系统拍摄了不同溶剂含量推进剂的燃烧波结构图片。结果表明,药柱内部至表面溶剂含量近似于线性分布;溶剂含量降低,溶剂浓度梯度下降,10~22 MPa推进剂燃速和燃速压强指数提高;溶剂含量降至1.1%以下,燃速趋于恒定。溶剂对AP/CMDB推进剂燃烧性能的影响机理为:溶剂的存在降低了推进剂的燃温和燃烧热值,减少了气相反应区向燃烧表面的反馈热量,使推进剂燃速降低。     

固体火箭发动机装药结构完整性研究进展

针对固体火箭发动机装药结构完整性的计算与评估问题,总结与分析中外复合固体推进剂本构模型、结构完整性解析模型、结构完整性数值仿真.研究表明:首先,复合固体推进剂具有力学性能复杂的特点,分析影响复合固体推进剂力学性能的主要因素,为建立合适的本构模型提供方向;其次,复合固体推进剂不可压缩、大变形、黏弹性性能,对装药结构完整性计算精度具有重要影响,分析提高求解精度的处理方法,为结构完整性精确计算与评估提供基础;最后,总结结构完整性分析的解析模型,为验证数值仿真提供了解析解.通过总结与分析,为装药结构完整性分析提供方向,为进一步优化装药设计提供理论基础.     

丁羟推进剂结构状态与力学性能的相关性研究评述

贮存过程中的老化使丁羟复合固体推进剂的结构状态发生变化从而对其力学性能产生影响,严重影响推进剂装药的结构完整性和发动机的使用寿命.针对这一问题,国内外相关学者进行了大量的研究工作.从理论研究与实验研究两方面介绍了国内外该领域的相关研究进展,重点对研究取得的主要成果和存在的问题进行了分析评述.通过分析总结,指出了本领域未来的研究方向和研究重点,提出了具体的研究思路.分析认为,丁羟推进剂作为一种固体填料填充的高分子复合材料,其结构状态与力学性能密切相关.从推进剂的化学结构、网络结构和微观结构等方面来研究其结构状态与力学性能的相关性,对揭示固体推进剂化学-力学关联失效机理颇有裨益.     

粒铸工艺对无烟EMCDB推进剂压强指数的改进

将粒铸工艺应用于改性双基弹性体（EMCDB）推进剂的成型，制备出了力学性能好、具有燃烧平台的无烟EMCDB推进剂，研究了燃烧催化剂、硝化棉含量和黑索今粒度对粒铸无烟EMCDB推进剂压强指数的影响，分析了粒铸无烟EMCDB推进剂具有较低压强指数的原因，说明在降低压强指数方面粒铸工艺比配浆浇铸工艺具有优势。     

离心浇铸挤压复合钢管界面组织与性能

采用离心浇铸挤压工艺制备了20Cr/1Cr18Ni9Ti复合钢管. 通过扫描电镜研究了试制复合钢管界面区域的显微组织,利用拉伸实验和热疲劳实验测试了其力学性能. 结果表明,采用离心浇铸挤压工艺生产的复合钢管实现了界面完全冶金结合,界面结合强度大大提高,界面处存在的过渡区增强了复合管的加工、使用性能. 采用此新工艺生产的复合钢管具有较好的组织和性能,并且工序简短,生产成本低.     

少梯膨化硝铵震源药柱的研究

在普通硝酸铵中加入专用表面活性剂和水,进行溶化－真空结晶处理,制得一种含有微气泡的硝酸铵,将这种改性硝酸铵称为膨化硝酸铵。由于膨化硝酸铵中含有许多微气孔,其比表面积大,具有自身敏化的特性,其起爆感度有明显提高。用膨化硝酸铵替代原用普通硝酸铵,震源药柱内装药中的梯恩梯含量降低５０％。文中论述了建构震源药柱内装药配方设计数学模型的方法。给出了少梯膨化硝铵震源药柱的３种配方和爆炸特征数据。     

高固体含量水反应金属燃料推进剂的力学性能

为研究高固体含量水反应金属燃料推进剂力学性能的影响因素,运用单向压缩方法和针入度测试,研究了不同工艺参数对铝镁水反应金属燃料推进剂在常温下的力学影响. 实验结果表明,工艺参数对推进剂体系中黏合剂网络结构的形成及向表面的迁移是造成体系力学性能改变的主要原因;水反应金属燃料推进剂压缩性能和硬度随固化参数和保压时间增加而增大,R值从0.9~1.0以上时,保压时间从5~25 min,其力学性能增幅较快,预固化3 h力学性能最好. 模压力增大造成体系中黏合剂组分向表面迁移加剧,力学性能随模压力增大而降低.      

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.     

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.     

A computer generator for randomly layered structures

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

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.