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1.
姜勇 《甘肃科技》2000,16(2):20-21
液压油的主要作用是接受原动机所产生的机械能转化成的压力能或动能 ,传递给工作机进行做功 ,同时 ,液压油还起到了对系统进行润滑、防腐、防锈和冷却的作用。根据工作机所利用能量方式的不同 ,将其分为液压油和液力传动油。依工作压力 ,我国把液压系统(液压泵、控制阀、油缸、油马达等)分为 :低压级(0~2.5MPa)、中压级(2.5~8MPa)、中加压级(8~16MPa)、高压级(16~32MPa)和超高压级(>32MPa)。1性能1.1液压油的粘度关系到设备的润滑、泄漏效率、准确灵活性和工作可靠性。粘度过大 ,系统…  相似文献   

2.
测试出油阀不同开启压力下的供油特性和动态供油开始点的变化,研究出油阀开启压力对多缸喷油泵各缸供油不均匀性的影响。ZHBF4喷油泵最佳的出油阀开启压力范围应为1.8MPa~2.6MPa。  相似文献   

3.
吴胜光 《广西科学》1994,1(2):70-76
对龙滩电站碾压砼坝的断面设计计算.提出:建基面的抗滑稳定与碾压砼层间稳定不同;龙滩碾压砼的胶凝材料用量按不同高程上、中、下三个层次进行碾压砼级配选择.上部水泥60kg/m3.粉煤灰90kg/m3;中部水泥用量65kg/m3.粉煤灰100kg/m3;底部水泥用量75kg/m3.粉煤灰105kg/m3。碾压砼的层间抗剪强度指标上部f'为1.1.c'为0.8MPa;中部f'为1.1,c'为1.0MPa;底部f'为1.1.c'为1.3MPa。碾压砼的层间稳定计算.采用不同安全系数计算式,即基本组合;Kf'采用2.0;Kc'采用10;坝的宽高比在0.75~0.8之间较为理想。  相似文献   

4.
注硼系统是确保反应堆安全的重要设施。文中实验研究了喷射泵在核反应堆注硼系统中作为安全装置使用的可行性和可靠性,实验的压力为0.1~1.5MPa,温度为20~198℃,喷射泵工作喷嘴直径为1~8mm,注入流量为0.1~0.8kgs-1。实验表明合理设计的喷射泵能满足“正向”注硼和“反向”阻断液位下降的双重作用。以实验研究为基础设计制造的喷射泵已首次应用于5MW核供热堆注硼系统中。  相似文献   

5.
一负压操作的蒸发器要求其环形管板能承受0.1MPa的压力,在有限元计算中,列管对管板的支撑作用由8个同心圆筒来模拟,计算结果表明该管板在0、1MPa的压力作用下,板内应力未超过许用值。  相似文献   

6.
玻璃纤维增强环氧树脂单向复合材料的研究   总被引:5,自引:0,他引:5  
采用连续玻璃纤维与环氧树脂相复合,通过单向缠绕成型工艺,制备出具有良好力学性能的单向复合材料板.研究了复合材料的成型工艺及配方组成对单向复合材料力学性能的影响,结果表明:采用成型工艺方法和配方组成的复合材料的拉伸强度为114GPa、弯曲强度为278MPa、冲击强度为347MPa;同时利用扫描电镜对复合材料的界面进行了分析.  相似文献   

7.
SiC长纤维增强玻璃陶瓷基复合材料的研究   总被引:4,自引:0,他引:4  
采用涨浆浸渍热压工艺制备KD-1SiC长纤维增强玻璃陶瓷其复合材料。研究烧结温度和纤维体积分数对复合材料力学的影响。SiCf/BAS复合材料的抗弯强度和断裂韧性最大达到494.1MPa和18.28MPa.m^1/2,SiCf/MAS复合材料的抗弯强度和断裂韧性最大达到538.7MPa和16.70MPa.m^1/2。结合试样的断口形貌和抗载荷-位移曲线分析了复合材料的失效方式。  相似文献   

8.
依据孤岛、中原、克拉玛依原油馏分油压力下(0.493~1.474MPa)228个窄馏分汽液相平衡常数,回归出K值关联式,该式对泡点温度预测的绝对平均偏差为4.7℃。根据实测数据,对常用热力学模型(SRK、SHBWR、CSGS)进行了适用性考察。结果表明,SRK方程预测精度最高,其对温度预测的绝对平均偏差为8.6℃,对K值预测的平均绝对相对偏差为8.7%。  相似文献   

9.
在压力连续微反-色谱装置上,以正己烷为反应物,研究了用非贵金属Ni和Mo改性的ZSM-5催化剂的异构化催化性能。逐步负勒Ni和Mo后,HZSM-5催化剂的催化性能逐渐提高。在空速为2h^-1,氢烃摩尔比为8.1,压力为1.5MPa,反应温度为230℃的条件下,当Ni含量为1.0%、Mo含量为2.0%时,催化剂的异构化活性、选择性和转化率分别高达18.6%、39.9%和46.6%。  相似文献   

10.
以植物油沥青为主要原材料,经醇酸酯化和改性处理,再加入适量的交联剂、催干剂。可以获得相当于桐油比强度1.2~1.5MPa/1%的粘结剂。  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.
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   

13.
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   

14.
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   

15.
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-  相似文献   

16.
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-  相似文献   

17.
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  相似文献   

18.
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  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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