去应力退火对DZ125合金再结晶行为的影响

为了获得具有优异高温力学性能的定向凝固高温合金,减少定向凝固叶片在生产过程中产生再结晶的现象,对经过喷丸后的DZ125合金进行了去应力退火处理,随后对其进行了不同温度下的热处理.利用扫描电子显微镜观察了DZ125合金的微观组织.结果表明,当表征喷丸强度的Almen值为0.25 mm时,依次进行870℃/500 h去应力退火与1 000℃/4 h热处理后,DZ125合金中仍存在少量胞状再结晶.经过1 150℃/4 h热处理后,胞状再结晶层厚度约降低30%;经过1 230℃/4 h热处理后,等轴状再结晶层厚度总体约降低了30%.当Almen值为0.17 mm时,在870℃下进行不同时间的去应力退火处理与1 230℃/4 h热处理后发现,随着退火时间的增加,再结晶层厚度逐渐降低,当退火时间为500 h时,再结晶层厚度约降低50%.     

紧固件表面锰系磷化膜的制备及摩擦磨损性能

为了提高核主泵紧固件的摩擦磨损性能,采用三种磷化工艺在40Ni Cr Mo7钢表面制备了锰系磷化膜.采用多功能材料表面性能测试仪进行了往复摩擦磨损试验,并研究了在有无润滑条件下,不同工艺对磷化膜摩擦磨损性能的影响.采用扫描电子显微镜和能谱仪表征了磨损前后磷化膜表面的组织形貌和化学成分,并分析了其磨损失效机制.结果表明,通过工艺Ⅱ制备的磷化膜具有最优的摩擦磨损性能.磷化膜特有的孔隙结构具有储油能力,有利于改善其摩擦学性能.随着法向载荷的增加,磷化膜的塑性变形增大,抗剪切强度降低,且摩擦系数呈先缓慢下降后急剧上升的趋势.     

Simulation of X-ray pulsar signals with multiphysical properties

In view of the few and discontinuous X-ray pulsar data, based on the physical properties of the X-ray pulsar real data from the Rossi X-ray Timing Explorer (RXTE) spacecraft, this paper adopts the fast iterative method and the 10 μs time transformation model, simulates the X-ray pulsar signals which have the periodic property, spectral property, and the background noise property as well as a variety of delay effects. We design and implement simulation software which can simulate the X-ray pulsar signals with multi-physical properties. The results of comparing the real data and simulation data in the same situation show that the simulation noises and the actual noises have the same distribution, that the period stability of the simulated X-ray pulsar data agrees with the real data, with the error of only 0.43％, in different energy levels, that the simulated data's integrated profile and the real data's standard profile are highly correlated with the Pearson correlation coefficient of 0.99, and that under the 10μs time transformation model, the time conversion accuracy of the simulation data can reach 10^-7s, the error between the simulation and the real data being just only 10^-7s, which meets the time transformation accuracy. Therefore, the proposed method can realize the high-fidelity simulations and generate the continuous pulsar signal with many physical properties.     

吸湿发热纤维混纺针织物耐磨性和悬垂性研究

研究吸湿发热纤维混纺针织物的力学性能,就其耐磨性和悬垂性与纯棉织物、涤棉混纺织物做了对比,实验结果显示,吸湿发热纤维混纺针织物的耐磨性、悬垂性均优于纯棉,与涤棉混纺织物相比略差。通过对吸湿发热纤维混纺针织物力学性能的测试分析,为后续针织物的研究奠定基础。     

木棉纤维的性能及其在纺织上的应用

介绍了木棉纤维的形态结构、化学组成以及基本的物理和化学性能,并阐述了其在纺织领域中的最新应用现状。木棉纤维具有优良的抗菌性和保暖性,已成为服装好家用纺织品中首选的保暖填充材料,有较好的应用前景。     

芦荟纤维与粘胶纤维物理性能测试与分析

对芦荟纤维与粘胶纤维的拉伸性质、摩擦和抱合性质、卷曲弹性、耐热性和热稳定性进行了测试与分析。结果表明:芦荟纤维的断裂强度比粘胶高,芦荟纤维的断裂伸长率比粘胶低;芦荟纤维粘胶的静摩擦因数小于粘胶纤维的静摩擦因数;粘胶纤维间的抱合力比芦荟纤维间的抱合力大,但芦荟纤维的平滑性比粘胶纤维要好。粘胶纤维的卷曲数、卷曲率、卷曲弹性回复率和残留卷曲率均小于芦荟纤维。     

阵列微结构表面技术的研究进展

阵列微结构表面技术可以有效改善金属表面的力学性能,已逐渐在工程机械、现代交通、现代化工等领域得到广泛应用。对阵列微结构表面的典型形貌,制备方法和技术应用这三个方面进行了论述。面向更高的技术需求,探索具有优质高效特点的阵列微结构表面多物理场复合制备方法;寻找更宽领域的应用,并尝试将各种不同的微结构根据其自身性质分别应用于同一对象的多处局部表面,使应用对象整体性能达到最佳,将是今后阵列微结构表面技术的研究重点。     

基于BCJR的GMSK混合信号分离算法研究

针对GMSK混合信号单通道盲分离问题,提出将BCJR算法用于GMSK混合信号分离。根据GMSK信号连续相位的特点,通过建立混合信号模型的有限状态马尔科夫性,推导了利用BCJR算法实现GMSK混合信号分离过程。在不增加算法复杂度的情况下,选择每个时刻后验概率的多个极大值对分离算法进行了改进。仿真实验表明,在调制参数比较相近的条件下,即使相对幅度、相对相位、相对时延估计不够准确,改进算法仍能取得较好的分离效果。     

光子计数成像探测器电荷感应层Ge薄膜特性研究

为了研究光子计数成像系统中感应电荷层Ge薄膜的制备工艺,改善光子计数成像系统的成像稳定性,采用直流磁控溅射法在熔石英衬底上制备了Ge薄膜,分析了工作气体Ar气通入量对Ge薄膜沉积速率的影响,利用表面轮廓仪及四探针表面电阻仪对样品分别进行了表面粗糙度及电学性能的表征。结果表明：随着Ar气通入量的增加,Ge薄膜沉积速率先上升后下降,在Ar气通入量为15sccm时,Ge薄膜的沉积速率出现极大值;Ge薄膜的表面粗糙度及薄膜电阻率均随着Ar气通入量的升高而增大;薄膜越厚,其电阻受氧化影响越小,电学性能越稳定。     

Caking property and active components of coal based on group component separation

The content and the caking index of the heavy,the dense medium and the loose medium components of coal,obtained by extraction and stripping with CS_2/N-methyl-2-pyrrolidinone mixed solvent(1:1 by volume),were studied and correlated with the caking property of raw coals.Images of the three group components after heat treatment were analyzed.The results show that both caking index(G) and maximum thickness of plastic layer(Y) of coals have a good linear relationship with the content of the medium component;the dense medium and the loose medium components are the two key factors to determine the caking property of raw coals-they are the source materials of fluidity and swelling of coal,respectively;the heavy component without the swelling and fluidity was cohered by the other components;two new indexes,which can extend current understanding of the caking properties,were introduced.