开孔板连接件剪切受力机理的试验研究

提出新的开孔板连接件抗剪承载力测试方法.共进行七组21个试件试验,测试开孔板连接件的荷载-滑移关系,观测开孔板连接件的破坏形态.结果表明:每组试件的荷载-滑移曲线重复性较好,验证了本文提出的测试方法的合理性.根据试验结果,分析开孔板连接件的破坏性质及影响开孔板连接件抗剪承载力的因素.     

二元精馏理论塔板数的简化逐板计算法

本文给出了一种求算二元精馏理论塔板数的简化逐板计算法。提出了计算所用递推公式并列举了实例。结果表明这种方法其计算过程比Ｌ－Ｍ法简单并具有与其相同的准确性。     

二元精馏理论塔板数的简化逐板计算法

本文给出了一种求算二元精馏理论塔板数的简化逐板计算法，提出了计算所用递推公式并列举了实例，结果表明这种方法其计算过程比Ｌ－Ｍ法简单并具有与其相同的准确性。     

弹性基础板的积分方程解法

本文提出了基础板的积分方程解法.该法首先将以挠度W和反力?相耦合的微分-积分方程化成一个求W的积分方程和一个求?的微分式子,然后采用基于虚功原理的差分离散格式,建立了支配方程.文中给出了算例,并将计算结果与现有成果作了对比.对比结果表明,本文方法具有方程简单、未知数少、精度高等优点,可作为基础板分析的又一方法.     

5种蕨类植物木质部管状分子的研究

为研究蕨类植物木质部管状分子的类型及特点,分别对蕨(Pteridium aquilinum var. latiusculum)、银粉背蕨(Aleuritopteris argentea)、华北薄鳞蕨(Leptolepidium kuhnii)、荚果蕨(Matteuccia struthiopteris)和耳叶金毛裸蕨(Gymnopteris bipinnata var. auriculata) 5种蕨类的叶柄或根状茎维管束进行离析处理,并在光学显微镜和扫描电镜下观察和照相.结果显示: 1)5种蕨类植物中都有导管分子存在,耳叶金毛裸蕨除具有导管分子外,还有管胞; 2)导管分子普遍具有多穿孔板,穿孔板以梯状为主,偶有网状,但没有单穿孔板,各种蕨类的管状分子中都存在不同程度的纹孔膜残余; 3)蕨导管分子的端壁和侧壁分化明显,存在网状穿孔板,并具有纹孔二型性现象,以及多孔性纹孔膜和凹槽结构; 4)银粉背蕨叶柄导管分子的穿孔板有的与纹孔膜完整的壁相邻,根状茎导管分子的侧壁之间以"脊"状结构相隔; 5)华北薄鳞蕨叶柄导管分子中存在不连续穿孔板,根状茎管状分子的端壁和侧壁分化鲜明; 6)荚果蕨叶柄导管分子中存在网状-梯状混合型穿孔板; 7)耳叶金毛裸蕨叶柄中同时具有导管分子和管胞,导管分子的穿孔板有的与纹孔膜完整的壁相邻; 8)与被子植物相比,蕨类植物导管分子的特征在很大程度上体现了其原始性.     

模具温升对22MnB5硼钢裸板高温摩擦磨损特性的影响

采用自制板带式高温摩擦磨损试验机模拟实际热冲压条件下22MnB5硼钢裸板的高温摩擦过程,对模具进行预热,模拟了热冲压过程中的模具升温,并通过硼钢热冲压的摩擦因数、表面磨损形貌和截面图及基体组织图研究模具升温对硼钢裸板摩擦行为及机理的影响.结果表明:模具升温较低时,硼钢裸板与H13钢之间的摩擦因数基本稳定在0.5,其磨损机理以磨粒磨损和黏着磨损为主.当模具升温超过100℃,硼钢裸板摩擦因数随温度升高呈现下降趋势,在150℃和200℃分别为0.474和0.414,黏着磨损作用减弱.硼钢基体维氏硬度在室温至100℃基本稳定在430,随温度进一步升至150℃和200℃,硬度分别降至413.5和399.7,表明模具升温对成型件机械性能有显著影响.     

空心弹体垂直侵彻混凝土靶板的应变测试研究

提出一种新型的测量实验弹侵彻混凝土靶板过程中的弹体变形的测试方法.采用正向弹道技术,在空心弹体内壁粘贴应变片电桥电路和弹载存储器,测量、记录弹体的撞击变形行为,并通过地面计算机再现该过程.利用这种测试手段,在95 mm口径空气炮上进行了系列截卵形头部的35CrMnSi弹体以150～300 m/s的速度垂直侵彻无钢筋混凝土靶板的实验,成功测得应变时间历程曲线,并对应变曲线和侵彻过程弹体变形的对应关系进行了分析讨论.实验结果表明弹体在侵彻靶板的过程中,材料承受交替的压缩、拉伸变形.     

奇异摄动小参数上界的求法

研究了在线性连续奇异摄动系统中奇异摄动小参数的选取方法.提出了一种求该系统稳定性界的新方法,由实例可知这种方法比起原有的方法简便可行.     

大整数素性的计算机测试和软件实现

探索和研究了素数的寻找及其素性测试的理论方法,给出了由Atkin和Morain提出的确定性素性测试方法及其软件实现,即椭圆曲线素性测试方法（ECPP）.最后通过与另一确定性测试方法Jacobi Sum测试方法进行比较,取得了比较理想的结果.     

青海湖裸鲤的起源和花斑裸鲤的种群演化

通过线粒体Cytb基因全序列分析,探讨了青海湖裸鲤和花斑裸鲤的起源关系及其进化模式.系统发育分析进一步支持了青海湖裸鲤和花斑裸鲤3个mtDNA谱系的划分.形态上具有高鳃耙变异的个体未形成特有的进化枝,证明了第一鳃弓外鳃耙变异并不具有系统发育意义.对青海湖裸鲤和花斑裸鲤进化枝扩散模式的网络分析表明,黄河独有的单倍型A1是一个创立者单倍型,全部青海湖裸鲤的样品来自于它的辐射,而青海湖裸鲤可能仅仅起源于黄河花斑裸鲤两个主要支系中的一个.Fs检验和核苷酸不配对分析暗示了青海湖裸鲤和柴达木盆地花斑裸鲤在历史上经历过种群扩张事件.青海湖裸鲤谱系多样化发生在大约0.2734Ma前,并且在约0.0658Ma前发生了一次局部的种群扩张,而柴达木盆地花斑裸鲤可能在约0.0693Ma经历了一次严重的“瓶颈效应”.我们还发现种群扩张存在于主要由青海湖裸鲤组成的亚枝A1和由黄河花斑裸鲤独有的亚枝A21中,估算的最近共同祖先年龄(TMRCA)分别为(0.2308±0.01)Ma和(0.1319±0.015)Ma,这一估算与青海湖和黄河分离的“共和运动”地质年代大致相符.这些结果说明了晚更新世末青藏高原的强烈隆升对青海湖、黄河和柴达木盆地鱼类多样性演化及其生物地理学格局产生过重大影响.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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