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1.
针对振动压路机一级橡胶减振系统的工作状态进行分析,推导出橡胶减振系统动刚度及动阻尼的计算方法,通过试验探究振动频率对橡胶减振系统动态参数的影响规律,指出随着钢轮振动频率的增加,橡胶减振系统的动刚度、动阻尼大致呈二次曲线规律变化,且与压路机低幅振动时相比,在同一振动频率下高幅振动时一级橡胶减振系统表现出的动刚度更大.对于试验样机而言,当振动频率为30~35 Hz时机架与钢轮的振动相位差最大,一级减振系统的动阻尼值最大.  相似文献   

2.
单质量盘转子扭振的动频研究   总被引:1,自引:0,他引:1  
在转轴以一定速度旋转的条件下,推导了考虑转动频率情况下的单质量盘转子扭振运动方程,通过有限元方法对不同几何结构的单质量盘转子在不同转动频率下的扭振固有频率进行了计算,对影响单质量盘转子扭振动频的动频系数进行了分析.分析结果表明,离心力的作用相当于使转子的扭转刚度增加,从而在不同程度上提高了转子的扭振固有频率,而在影响单质量盘转子扭振动频系数的因素中,动频系数与转子转速的平方及质量盘直径的平方成正比,而与质量盘厚度关系不大.由此结果得出了动频的计算公式,并在该计算公式的基础上提出了用于判断单盘转子是否需要考虑扭振动频的判定准则,该项工作对于旋转机械如何避开扭振固有频率的设计具有重要的指导意义.  相似文献   

3.
本研究评价了在高性能混凝土中掺加粉煤灰-硅灰或磨细矿渣-硅灰的不同组合时的抗压强度、劈拉强度和氯离子渗透性。在水胶比0.28~0.33、总胶凝材料用量500~550kg/m3下,采用这两种矿物掺和料组合替代30%~50%的硅酸盐水泥时,混凝土28d抗压强度大多为85~100MPa,28d劈拉强度大多为5.5~6.5MPa,并具有高工作性和很低的氯离子渗透性;混凝土的早期强度发展快,而且后期强度持续增长。含粉煤灰-硅灰或矿渣-硅灰的不同组合的混凝土的劈拉强度与抗压强度的比值为0.063~0.066。不存在一个对于抗压强度和劈拉强度都是最佳的掺和料组合。  相似文献   

4.
为了研究滇池泥炭质土中有机质成分对于土体动强度特性的影响,对不同有机质含量的饱和重塑泥炭质土进行室内动三轴试验,研究了不同有机质含量、固结压力、振动频率对重塑泥炭质土的动强度曲线的影响,分析了不同有机质含量、振动频率及循环振次控制条件下重塑泥炭质土的动强度指标的变化规律。得出结论如下:重塑泥炭质土的动剪应力在其他条件相同时,均随着固结压力、振动频率和有机质含量的增加而增大。其中有机质含量对重塑饱和泥炭质土的动强度影响最大,土体动强度指标随有机质含量增加呈明显正相关性。重塑饱和泥炭质土动强度受荷载振动频率的影响较小,动强度指标总体上随振动频率的增大有小幅提升。循环振次则对重塑饱和泥炭质土动强度呈负相关影响。  相似文献   

5.
对海南铁矿烧结燃耗高的原因及降低燃耗的途径进行了研究.试验结果表明:用30%澳矿代替海南粉矿,燃耗从101.8kg/t降到90.25kg/t;添加0.03%添加剂,随着料层高度增加,节能效果变得明显,但是当料层高度超过450mm时,生产率降低;焦粉分加,可使焦粉配比由7.0%降到6.2%~6.5%,燃耗由96.65kg/t降到83.25kg/t.  相似文献   

6.
将处于静态平衡状态的柔弱夹层顺层岩体边坡在爆破振动作用下的滑移失稳问题,视为层面抗剪强度指标(φ、c)弱化造成的.通过爆破振动试验分析发现,在层面强度及振动频率一定时,随着爆破振动引起的质点振动速度的增加,柔弱夹层等效动内摩擦角和等效动粘聚力弱化值逐渐增大,且它们与爆破振引起的质点振动速度成幂函数关系,利用其关系可判断爆破振动作用下柔弱层面性质的顺层边坡的动稳定性.  相似文献   

7.
在设计铲刮头时,不仅要研究铲刮头浮动块的静特性.而且必须要研究其动特性,使铲刮头浮动块在铲刮磁盘高点时有良好的跟随性,提高铲刮质量。文中阐述了浮动块跟随振动的3种模态,着重分析了平行振动模态.进行了正压型浮动块和负压型浮动块的动特性设计。实验证明,经过静、动特性设计的铲刮头.能高效地铲刮高于0.2μm的高点。  相似文献   

8.
本文对“双向拉伸”的试验装置和测试技术进行详细研究,并在各向异性理论的基础上,研究了双向拉伸的各向异性虎克定律及其屈服条件,最后通过大量的双向拉伸试验,严格证明:①钛板具有明显的各向异性;②钛板有明显的双向强化效应;其屈服强度比其单向屈服强度高44~51%;③利用本文推导的公式,可以通过单向拉伸强度柬简捷地确定材料的双向拉伸强度.  相似文献   

9.
肖忆良  肖起游 《江西科学》1998,16(4):264-267
w=10%多效剂的波美度28~30;多硫化态硫≥10%,烟碱≥0.03%~0.05%;茶皂素≥0.14%;相对密度1.26;pH12~14,为茶褐色半透明液体。经过室内和田间小区药效试验及十余年的大田反复试验、试用,充分证明多效剂对农作物多种病虫有显著防治效果,对植物生理性病害有特别防治效果。  相似文献   

10.
观察不同剂量的扶桑花提取物在宫内注射大鼠的抗早孕效果.实验结果显示:(1)每侧子宫给予10mg,20mg和30mg的石油醚提取物(HR1)后,子宫内死胚和损伤胚的百分率分别达到81.6%,92.0%和99.0%,胚胎平均大小分别为0.30cm,0.31cm及0.17cm,明显小于对照组的胚胎0.75cm(P<0.01).(2)给药各组的血清FSH()和雌二醇呈下降趋势,血清LH()及孕酮水平仅在30mg剂量组明显低于对照组(P<0.05).这提示,HR1在大鼠的抗早孕作用与垂体和卵巢激素的降低有关  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
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。  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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。  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
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