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1.
我厂为山东龙口铝业集团生产的铝锭专用镗床Q1Z-021,两种规格镗杆分别为直径φb80mm和直径西130mm,为冷却刀头需在镗杆上加工-直径φ8mm的润滑小孔,孔长度为160mm,并且小孔中心距离外圆为φ8mm,即加工完成后的小孔壁距离外圆仅仅4mm(如下图所示)。  相似文献   

2.
螺纹钢锚杆直径与钻孔直径的合理匹配   总被引:2,自引:0,他引:2  
以大量的实验室和现场试验为基础 ,从技术经济上深入研究了螺纹钢锚杆直径与锚杆外孔直径的合理匹配关系。研究结果认为 ,锚杆钻孔直径为 2 8mm ,使用直径为 2 2mm的无纵筋螺纹钢筋锚杆或直径为 2 0mm带纵筋建筑螺纹钢筋锚杆 ,可以取得较大的锚固效果和较好的经济效益。  相似文献   

3.
水刺非织造材料经后整理后用作建筑工程中的屋面防水材料,不仅要具备良好的透湿透气性能,还需具备优良的抗撕裂特性.基于欧洲标准中屋面防水卷材撕裂性能(钉杆法)的测试方法,通过改变钉杆撕裂试验中夹持距离、拉伸速率、钉子尺寸等各试验参数,分析了试验参数变化对试验结果的影响.结果表明:对屋面防水用涤纶短纤水刺非织造材料撕裂性能采用钉杆法测试,试验参数设为试样宽度为100mm、钉子孔中心距上夹持器的距离为100mm、拉伸速率为100mm/min、钉子直径为2.5mm、钉子孔中心距试样下端边缘的距离为65mm时,测试方法较合理,能较客观反映材料的撕裂性能.  相似文献   

4.
孙慧  袁子洲  乔宇  张英明 《甘肃科技》2010,26(15):44-45
采用搅拌摩擦焊接技术对Zr44Ti11Ni10Cu10Be25块体金属玻璃和紫铜进行了连接,当旋转速度为600r/min、摩擦头直径为2mm、焊接速度为40mm/min、轴肩直径为12mm、压入量为0.1mm时,能够成功实现焊接,利用XRD、DSC、SEM观察分析未检测到晶化相,焊缝处试样仍保持非晶状态。  相似文献   

5.
本文在多年试验和实践基础上,提出一种对大直径的内螺纹的高精度挤压加工方法,(在此之前其应用仅对铝、铜等有色金属和低炭结构钢并局限于16mm以下小直径)。总结出内螺纹的螺纹精度直接取决于丝锥的精度,而螺纹孔的位置精度却有赖于攻丝前螺纹底孔的位置精度。到本文发表时止,已成功地发展出一种高速精钻工艺来制备铬钼合金钢连杆的螺纹底孔,和一种尺寸达22—36mm的系列无槽丝锥的挤压攻丝技术以精加工内螺纹。其结果是一次挤压可获得一级螺纹精度和V7的表面光洁度,螺纹抗拉强度增加20—30%,抗剪强度增加5—10%,表面硬  相似文献   

6.
采用普通机械方式对不同层数二维三轴编织铺层复合材料进行开孔,并对开孔前后材料的弯曲性能进行研究.结果表明:当孔直径与试样的宽度比为1∶3.88时,铺层数为一、二、三的编织复合材料开孔后最大弯曲载荷和弯曲强度较开孔前分别下降了1/3左右;弯曲弹性模量分别下降了1/2左右.开孔前后试样的最大弯曲载荷和弯曲弹性模量都随着铺层数的增加而增加,但当铺层数达到一定层数后,对弯曲性能的改变量减小.材料弯曲破坏试验中表现的主要破坏模式为压缩破坏.开孔对周围的影响主要为距孔边缘1~2mm范围.  相似文献   

7.
文章制备了一套限定型高压扭转(HPT)设备.采用HPT处理纯铜试样,对比处理前后试样几何尺寸,观察试样与砧头之间的相对滑动,结果表明,HPT处理前后试样厚度变化小于5%,试样端面和模具不发生相对滑动.用量纲分析和有限元方法分析试样的变形,得到切应变和厚度/直径、压力/材料弹性模量以及模具侧面的摩擦状况相关;直径8 mm厚0.86 mm纯铜试样上r<3.2 mm区域的变形可以用纯扭转来描述.  相似文献   

8.
本文用孔结构仪对哈密弱-中性膨胀土原状试样、重塑试样和风干重塑试样,进行了微观结构对比试验,获得大量珍贵的膨胀土微观结构照片。对哈密膨胀土微观结构对比试验数据和照片分析研究可得:膨胀土的特殊微观结构可能是膨胀土膨胀特性的又一重要影响因素;不同干密度、含水率的重塑土样微观结构具有一定的规律,含水率越大、干密度越小,土样表面孔隙面积越大,孔隙越多,孔隙直径越大,孔隙直径分布越分散;原状样孔隙主要为0~0.1 mm的孔隙,重塑土大多为0~0.2 mm的以0.1 mm为峰值的孔隙。  相似文献   

9.
采用水冷铜坩埚-铜模吸铸法成功制备了底部直径10 mm、长度80 mm的Cu50Zr42Al8圆锥形块体非晶试样.利用X射线衍射,光学显微镜和SEM、TEM等测试手段对圆锥形试样轴向和径向微观结构的特点和微观组织的演变进行了研究.结果表明,由于冷却速率的不同,圆锥形试样的显微组织由表面非晶区、中心等轴晶区及介于两区之间的过渡区组成.过渡区由非晶和晶体相组成,晶体的尺寸和体积分数由表面向中心逐渐增加,具有梯度变化的特征.  相似文献   

10.
铜包铝复合棒充芯连铸设备的开发   总被引:7,自引:0,他引:7  
为了实现以铝代铜,开发铜铝复合材料,设计和制造了一台制备铜包铝复合棒坯的充芯连铸试验机.该机器的特点为:结晶器为水冷铜套内衬石墨套;在高度方向上设置一高一低直径不同的加热器,下加热器与结晶器相连接在此试验机上;充芯与连铸同时进行.利用该设备,成功地连铸出芯部直径为φ24mm,外层厚度为8mm的铜包铝双金属复合棒.  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.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

14.
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.  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.
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   

18.
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   

19.
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   

20.
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   

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