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1.
陈怀筹 《株冶科技》1997,25(1):30-31
这篇文章就影响铜阳极模使用寿命的炸裂和龟裂现象进行了探讨,从铸造原理角度分析了产生炸裂的原因并从金属学角度提出铜阳极模应具有的金相组织,从金属学及物理化学角度分析了产生龟裂现象的原因并从金属学角度提出了铜阳极模应具有的金相组织,分别从技术工艺和材质方面提出了改进措施。  相似文献   

2.
介绍了鼓风机的静叶角度调整原理与方法,通过调节鼓风机的静角度改变鼓风机的工作点,从而达到恒定风量控制风压的目的。  相似文献   

3.
李志红 《云南冶金》2006,35(4):67-70
在改进原有实验条件的基础上,通过对原有X射线的小角散射理论进行修正及合理简化,从而建立了新的数学模型。并借助计算机进行数据处理,大大地提高了数据处理的效率。实验中通过接装角度显视仪,使我们能精确地测定出散射的角度,并在该角度下延时测量散射强度。有效地解决了样品薄所带来的散射强度弱的问题,提高了角度测量的精度。同时也为理论研究提供了可靠的依据。通过对比,新的数据处理方法与其它数据处理方法得到的结果吻合。这证明了该数字模型的可靠性和实用性。  相似文献   

4.
在复合力试验中,通过建立合理的力学模型,利用测量水平位移量计算管样角度变化,解决了试样角度无法直接测量的问题。此试验方法客观地模拟了井况,得到油田用户的肯定,满足了用户的需求。  相似文献   

5.
钟梅梅 《河北冶金》1998,(2):70-74,114
介绍了鼓风机的静叶角度调整原理与方法,通过调节鼓风机的静角度改变鼓风机的工作点,从而达到恒定风量控制风压的目的。  相似文献   

6.
介绍了物料在变角度下如何计算重量,以及变角度显示仪的工作原理和在实际中的运用。  相似文献   

7.
方爱民  刘小鸥 《炼钢》1995,11(1):3-6
本文总结了双角度氧枪在生产实践应用中的经验,并与6孔30°、6孔23°氧枪进行对比,确定了双角度氧枪的优点。  相似文献   

8.
介绍了物料计量秤在变角度下如何计算重量,以及变角度显示仪的工作原理和在实际中的运用。  相似文献   

9.
单庆斌 《昆钢科技》2000,(3):28-30,24
对破碎机保险本体零件断裂损坏进行了多角度分析,从检修维护角度和设计改进等方面提出了改进措施。  相似文献   

10.
为了探究初始微裂纹参数分布对岩石破裂特征及力学性能的影响,进一步系统地了解脆性岩石破裂演化过程,依据线弹性断裂力学理论,建立了非均质性二维细观弹性损伤模型,并运用FLAC2D数值分析软件,数值模拟研究了单轴压缩条件下不同形态岩石试样的破裂过程。研究结果表明,当初始微裂纹长度和角度服从不同的随机分布时,岩石材料表现出不同的破裂特征,其中初始微裂纹长度和角度均服从正态分布时,岩石破裂区域较完整;初始微裂纹长度或角度服从均匀分布和指数分布时,岩石破裂区域较分散;初始微裂纹角度对于解释脆性岩石单轴抗压试验时岩石试样出现剪切破坏和劈裂破坏的原因具有一定的指导意义,且当初始微裂纹角度均值ɑ=45°时,模型具有最小的峰值强度和轴向最大应变。模型还模拟了脆性岩石单轴抗压试验、巴西劈裂试验和断裂韧度试验的演化过程,模拟结果与试验结果具有较高的一致性。  相似文献   

11.
Within-child associations between family income and child externalizing and internalizing problems were examined using longitudinal data from the NICHD Study of Early Child Care and Youth Development (2004a, 2004b; N = 1,132). Variations in income effects were estimated as a function of whether families were poor, whether mothers were partnered, and the number of hours mothers and their partners were employed. On average, children had fewer externalizing problems during times when their families' incomes were relatively high than during times when their families' incomes were relatively low; the estimated benefits of increased income were greatest for children who were chronically poor. For both externalizing and internalizing problems, income was most strongly associated with problems when chronically poor children's mothers were partnered and employed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

12.
系统汇集了20世纪70年代以来我国使用X射线荧光光谱(XRF)分析技术进行铁矿石分析的文献共计101篇,其中熔融制样法文献78篇,粉末压片法文献11篇,能量色散仪器分析及野外现场应用文献12篇。首先介绍了铁矿石分析的基础条件:包括专著、标准物质、标准方法和综合性评述论文;然后采用表格方式对文献要点进行了介绍, 按熔融法、粉末压片法、能量色散多元素分析方法进行了重点评介;最后讨论了铁矿石分析中常遇到的粒度、矿物效应,制样方法选择和内标的应用等实际问题。对XRF在铁矿石分析中的某些重要问题进行了探讨,并对XRF分析铁矿石的应用前景作了展望。文献表明:XRF技术已经成为铁矿石主、次量元素分析最重要的分析方法之一。全篇引文151篇。  相似文献   

13.
通过2种途径将熔体快淬法制得的FeCuNbSiB非晶薄带制成环状粘结磁体。一是将非晶薄带进行晶化处理,再将晶化后的薄带粉碎成不同粒度的粉末,然后与粘结剂相混合制成粘结磁体。二是将非晶薄带直接粉碎成不同粒度的粉末,再将此粉末进行晶化处理,将晶化后的磁粉与粘结剂相混合制成粘结磁体。分析了磁粉粒度和模压压力对粘结磁体性能的影响。并对两种粘结磁体的性能进行比较。结果表明,第一种方法制备的粘结磁体的性能优于第二种。  相似文献   

14.
系统汇集了20世纪70年代以来我国使用X射线荧光光谱(XRF)分析技术进行铁矿石分析的文献共计101篇,其中熔融制样法文献78篇,粉末压片法文献11篇,能量色散仪器分析及野外现场应用文献12篇。首先介绍了铁矿石分析的基础条件:包括专著、标准物质、标准方法和综合性评述论文;然后采用表格方式对文献要点进行了介绍, 按熔融法、粉末压片法、能量色散多元素分析方法进行了重点评介;最后讨论了铁矿石分析中常遇到的粒度、矿物效应,制样方法选择和内标的应用等实际问题。对XRF在铁矿石分析中的某些重要问题进行了探讨,并对XRF分析铁矿石的应用前景作了展望。文献表明:XRF技术已经成为铁矿石主、次量元素分析最重要的分析方法之一。全篇引文151篇。  相似文献   

15.
A geotextile-reinforced embankment was built over soft ground. Staged construction and vertical prefabricated drains were used to obtain strength gain via consolidation of the foundation material. Settlement and pore pressure were measured as a part of construction control. Settlement, differential settlement, and rate of consolidation were predicted by simple models. Uncertainties in the predictions were evaluated to assess the reliability of the predictions. The estimated errors were compared with the measured values, and major contributors to prediction errors were identified.  相似文献   

16.
In this paper, efficiency and effectiveness of carbon fiber-reinforced polymers (CFRP) in upgrading the shear strength and ductility of seismically deficient beam-column joints have been studied. For this purpose, four reinforced concrete interior beam-column sub-assemblages were constructed with nonoptimal design parameters (inadequate joint shear strength with no transverse reinforcement) representing preseismic code design construction practice of joints and encompassing the vast majority of existing beam-column connections. Out of these four, two specimens were used as baseline specimens (control specimens) and the other two were strengthened with CFRP sheets under two different schemes (strengthened specimens). In the first scheme, CFRP sheets were epoxy bonded to the joint, beams, and part of the column regions. In the second scheme, however, sheets were epoxy bonded to the joint region only but they were effectively prevented against any possible debonding through mechanical anchorages. All four subassemblages were subjected to cyclic lateral load histories so as to provide the equivalent of severe earthquake damage. Further, the damaged control specimens were repaired after filling the cracks through epoxy and wrapping them with CFRP sheets under the same two above-mentioned schemes. These repaired specimens were subjected to the similar cyclic lateral load history and their response histories were obtained. Hence, a total of six specimens were tested: two control; two strengthened; and two repaired. Response histories of control, repaired, and strengthened specimens were then compared. The results were compared through hysteretic loops, load-displacement envelopes, column profiles (maximum horizontal displacements of column along its height), joint shear distortion, ductility, and stiffness degradation. The comparison shows that CFRP sheets improve the shear resistance of the joint and increase its ductility. Results of two chosen schemes of strengthening were also compared and the importance of beam upgrading was highlighted.  相似文献   

17.
15-5PH steel is one of the martensitic precipitation-hardened stainless steels, which is extensively applied in the aero shafts, and electron beam welding is a significant procedure to manufacture the parts. To verify the dimension accuracies and properties, EBW with oscillation was employed on the cylinders of 15-5PH steel. The welding distortions were measured, and the microstructures and tensile properties of the joints were investigated. The weld appearances of the cylinders were smooth, and the morphology was parallel. After EBW, the shrinkages of the cylinders were above ?0.22?mm, and the welding distortions were ?0.66 to ?1.1‰, and the straightnesses were less than 1‰ due to the distortions. The martensites and a few austenites were in the welds of the cylinders after heat treatment, and the microhardnesses in the welds were 445 HV0.2, which were bigger and more homogeneous than those of the as-welded. The tensile strength and yield strength of the joints were respectively 1300 and 1150?MPa, which were higher than those of the as-welded joints, and the elongation rate of the joints was 10%. The microstructures and properties of the cylinders conformed to the aero shafts, which was attributed to the microstructure transformation with oscillation EBW and heat treatment.  相似文献   

18.
全层TiAl基合金室温断裂机制的研究   总被引:1,自引:1,他引:1  
通过拉伸、压缩、弯曲实验分析研究了全层(FL)组织TiAl基合金的断裂机制。研究发现:拉伸和压缩时材料抵抗裂纹的扩展能力不同,抗压强度远高于抗拉强度,这是由于两者的变形及断裂机制不同。TiAl基合金拉伸断裂机制为脆性解理断裂,压缩变形断裂是剪应力和正应力共同作用下的断裂,是准解理断裂。TiAl基合金的缺口弯曲断裂方式也为解理断裂,其断裂过程是先在缺口处产生微裂纹,一旦裂纹在缺口根部产生,由于材料已积累足够的能量使得材料快速失稳解理断裂。  相似文献   

19.
通过辉光放电质谱法(GDMS)测定了高温合金中的C,Mg,Al,P,S,Ti,V,Cr,Mn,Fe,Co,Cu,Nb,Mo,W共15种元素。对辉光放电参数如电流、电压、预溅射时间进行了优化;对高温合金中的质谱干扰进行了分析并详细叙述了各分析元素的干扰情况。选择丰度大且不受干扰或干扰少的同位素用于分析,大多数元素测定结果很好。对于仍存在干扰的元素通过数学校正的方法进行质谱干扰校正。建立干扰校正公式,成功地消除了62Ni2+和36Ar12C+对31P+和48Ti+的质谱干扰。在优化的实验条件下,建立工作曲线。  相似文献   

20.
Three experiments with paired comparisons were conducted to test the noncompensatory character of the recognition heuristic (D. G. Goldstein & G. Gigerenzer, 2002) in judgment and decision making. Recognition and knowledge about the recognized alternative were manipulated. In Experiment 1, participants were presented pairs of animal names where the task was to select the animal with the larger population. In Experiment 2, participants chose the safer 1 out of 2 airlines, and 3 knowledge cues were varied simultaneously. Recognition effects were partly compensated by task-relevant knowledge. The compensatory effects were additive. Decisions were slower when recognition and knowledge were incongruent. In Experiment 3, compensatory effects of knowledge and recognition were found for the city-size task which had originally been used to demonstrate the noncompensatory character of the recognition heuristic. These results suggest that recognition information is not used in an all-or-none fashion but is integrated with other types of knowledge in judgment and decision making. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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