基于随机过程理论短螺旋钻头载荷的数学模型

为了揭示短螺旋钻头载荷随切削厚度和岩石接触强度变化规律,根据岩石的物理力学特性,结合单个镐型截齿切削破岩的工作机理和短螺旋钻头的结构特征,分析短螺旋钻头入岩工况下的受载情况;运用随机过程理论,建立短螺旋钻头随机载荷的数学模型.针对不同的岩石接触强度和钻头切削深度,借助MATLAB仿真求解钻头的扭矩和轴向力,采用数学统计方法对实测结果进行处理分析,并与理论值相比较.研究结果表明:理论求解的钻头扭矩和轴向力的幅值与均值和实际测试值都比较接近,且两者的变化规律一致;在切削厚度一定时,扭矩和轴向力的幅值和均值随着岩石接触强度的增大而迅速增大;在岩石接触强度一定时,扭矩和轴向力的幅值和均值也会随着切削厚度的增大而迅速增大.     

螺旋式S型风轮气动性能试验研究

为了克服传统S型风轮扭矩波动大的缺点,提出了一种偏转180°螺旋式S型风轮,在低速风洞进行风洞气动性能试验.风轮的旋转直径420mm、高度680mm、偏心距100mm,测量了风轮在风速5m/s不同相位角对应的静扭矩以及风速10m/s不同负载下的转速与扭矩.通过对实验数据分析得出:螺旋式S型风轮始终产生促使转动的正的扭矩,叶尖损失造成静扭矩不随相位角恒定分布,但是静扭矩波动较小;风轮转速波动幅度随着尖速比的增大而减小,扭矩波动幅度随着尖速比的增大而减小;风轮扭矩系数是尖速比的一次函数且随着尖速比增大而减小,功率系数是尖速比的二次函数且截距为零,功率系数随着尖速比增大先增大后减小.     

采煤机滚筒截齿排列的试验研究

根据采煤机破煤理论,研制煤岩截割试验台;根据不同的滚筒叶片截齿排列、螺旋叶片头数,研制4种不同的试验滚筒.以此为基础,在试验台上对4种不同截齿排列的滚筒进行截割性能试验,分析不同滚筒截割扭矩的最大值、最小值、均值、方差等参数;同时,对截落煤岩的块度进行分级处理,研究不同截齿排列滚筒截割块煤率.研究结果表明:对同一直径、不同叶片头数、不同截齿排列的滚筒,在截割时,随着螺旋叶片头数的增多,其载荷波动性减小;在2头螺旋叶片滚筒中,棋盘式滚筒的扭矩均值、方差等统计参数值均比顺序式的小,而棋盘式的块煤率比顺序式的大;具有3头螺旋叶片的畸变Ⅰ式和畸变Ⅱ式滚筒,在截割扭矩的统计参数值中除畸变Ⅰ式的方差小于畸变Ⅱ式的方差外,其余参数基本相等;并且,在4种滚筒中,畸变Ⅰ式截割时滚筒载荷的波动性最小,块煤率最大.     

组合转子阻垢特性的实验研究

针对在换热器运行中起强化传热与自清洁作用的内插件组合转子进行了实验研究。实验测得光管、内置螺旋两叶片开槽转子和螺旋纽带的换热管内单位面积污垢沉积量随时间的变化趋势,并得出内置组合转子换热管在不同流速和不同水浴温度下的阻垢特性。实验结果表明：相较于光管,螺旋两叶片开槽转子与螺旋纽带都具有较好的阻垢特性,而螺旋两叶片开槽转子阻垢性能更优,污垢渐近值为螺旋纽带的72%;随着流速的增加,内置组合转子换热管内污垢渐近值减小,且达到渐近值所需时间延长,阻垢性能增强;水浴温度的提高使污垢渐近值增大,达到渐近值所需时间缩短,阻垢性能减弱。     

液体体积弹性模量与矿化度关系测量实验研究

介绍了采用超声光栅效应测量液体体积弹性模量基本原理,设计组装了实验测量装置,测定了在不同矿化度下液体体积弹性模量.根据实验数据分析了液体体积弹性模量的变化规律、在同一温度时水溶液体积弹性模量随着矿化度的变化规律.实验表明:随着矿化度的增大,液体体积弹性模量会先增大后减小.     

油气两相动压密封端面结构多参数正交优化及试验研究

针对油滴均匀分布在气相中的油气两相动压密封,利用Fluent软件建立两相动压密封端面间流体模型,并采用多参数正交优化法,分析密封性能参数（工作膜厚、流体膜刚度、泄漏量及摩擦扭矩）随两相密封动压槽结构参数（螺旋角、槽深、槽宽比、槽坝比和槽数）的变化。分析结果表明：在恒定转速、压差和闭合力条件下,通过调整各结构参数均可获得最大工作膜厚;流体膜刚度随着螺旋角和槽深的增大而减小;气体泄漏率和液体泄漏率随密封槽结构参数变化规律相同,且变化规律与工作膜厚相同;得到了定工况下的最优动压槽结构参数。最后通过自主设计的气液两相动压密封实验装置进行静压试验和运转试验,验证了动压密封在油气两相介质工况下应用的可行性。     

风电机组叶片模型变桨距载荷实验

以1.5MW变桨距风电机组叶片为原型,设计并制作叶片模型,分析叶片载荷特性,并通过电测法对叶片模型变桨距载荷进行测试分析.结果表明,在风速为4m/s时叶片拉应力随桨距角增大而增大的趋势,但不明显;随着风速的增大,叶片拉应力随桨距角的增大而减小,趋势明显.剪应力载荷随桨距角增大而呈现一致减小的趋势,各个截面变化规律相同.     

行人对人行桥三分力系数的影响

以风洞试验方法为主、计算流体力学(CFD)方法为辅,研究不同角度风嘴入流、行人密度和行人横向排列位置条件下的人行桥主梁断面三分力系数的变化规律.结果表明:桥上行人的存在会改变截面周围气流的流态,从而对桥梁断面的静力三分力系数产生显著影响;风攻角在-12°~12°范围内,阻力系数均呈现先增加后减小趋势,负风攻角范围内行人密度是阻力系数变化的主导因素,而正风攻角范围内阻力系数变化受风攻角主导;当风攻角由-12°变化到12°时,小风嘴入流状态下的升力系数和扭矩系数整体逐渐减小,而大风嘴入流状态下的升力系数和扭矩系数整体呈现先增大后减小的趋势,随着行人由迎风侧移动到背风侧,阻力系数略微增大,升力系数显著减小,扭矩系数几乎不变.     

履带车辆不同沟槽形式湿式摩擦副带排扭矩分析

为了模拟履带车辆变速机构湿式摩擦副的黏滞损失,分别对3种常用沟槽形式——径向槽、双圆弧槽和螺旋槽样件进行了带排扭矩的理论和实验分析.综合运用带排理论及CFD模型,获得不同沟槽形式的摩擦副的扭矩特性及适用工况;分析带排间隙和转速对摩擦副带排扭矩的影响程度;发现螺旋槽在不同旋转方向情况下有不同的扭矩特性;得出了在不考虑散热条件下螺旋槽摩擦副在履带车辆减小黏滞损失方面具备优势的结论.     

小型水平轴风力机在不同桨距下发电性能的实验研究

本文对一小型水平轴风力发电机的发电性能和叶片流场进行了实验研究.基于三种桨距,测出在不同的来流风速和不同负载下的电流和发电功率,分析得到随着负载的增大电流强度减小,而功率随着风速的增大先增大后减小,存在着峰值功率;结果也表明桨距对叶片风能利用率影响较大.基于桨距A=60°、来流速度3m/s和负载5Ω,采用粒子图像测速仪(PIV)技术对垂直于桨叶旋转平面的截面进行了流场测量,结果显示桨尖涡在风力机叶片流场中起主导作用.     

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.     

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.     

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.     

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.     

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.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

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.     

The Analects and the Moment in Peking——The influence of a Confucian education system on the personality formation,the way of thinking and the fate of the main characters

0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation＇s behavior in their social life throughout the long history is beyond list.