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为帮助材料检测实验室顺利通过NADCAP(国家航空航天和国防合同方授信项目)认证,对ASTM G34-01(2013)和NADCAP材料测试项目相关标准进行了解析,从试验设备、试验试剂、试样加工要求等方面介绍了进行剥落腐蚀试验时应注意的技术要点和实践经验。 相似文献
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在低温条件(TC≈3~22 K)下, 除了4f电子满壳层的LuB12之外, 其他稀土-硼十二化合物(简称RB12, R为稀土元素Tb, Dy, Ho, Er, Tm)存在磁性和比热的反常现象, 该反常现象的机制至今仍存争议。尽管磁化率曲线上的隆起与R3+离子的反铁磁序类似, 但是中子衍射谱和莫斯堡尔谱的实验均没有明确给出稀土离子的磁结构。这些化合物磁化率、熵的反常行为和低温中子谱的结果都与RB12具有幅度调制的磁结构一致。本课题组采用模型和数值计算相结合的方法来探究该反常行为的物理机制。研究表明: 由于稀土离子meV量级的晶场劈裂易受热涨落扰动, 晶场劈裂能不再是一个量子力学参量, 而是一个热力学序参量。物理图像中轨道角动量逐渐淬灭很好地解释了磁性和比热的反常现象。结合该类晶体低温下在(111)晶向的二聚化行为和非弹性散射谱的结果, 对中子散射谱中的双峰结构也给予了一个可能的解释。 相似文献
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Batch tests and column tests were performed to determine the design factors for permeable reactive barriers (PRBs) against the contaminated groundwater by ammonium and heavy metals. Clinoptilolite, one of the natural zeolites having excellent cation exchange capacity (CEC), was chosen as the reactive material. In the batch tests, the reactivity of clinoptilolite to ammonium, lead, and copper was examined by varying the concentration of cations and the particle size of clinoptilolite. One gram of clinoptilolite showed removal efficiencies of more than 80% against those contaminants in all cases except in very high initial concentrations of ammonium (80 ppm) and copper (40 ppm). The effect of particle size of clinoptilolite was not noticeable. In the column tests, permeability was examined using a flexible-wall permeameter by varying particle sizes of clinoptilolite. When the washed clinoptilolite having the diameter of 0.42-0.85 mm was mixed with Jumunjin sands in 20:80 ratio (w/w), the highest permeability of 2 x 10(-3) to 7 x 10(-4)cm/s was achieved. The reactivity and the strength property of the mixed material were investigated using a fixed-wall column, having eight sampling ports on the wall, and the direct shear test, respectively. Clinoptilolite was found to be a suitable material for PRBs against the contaminated groundwater with ammonium and/or heavy metals. 相似文献
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Yu. K. Blokin-Mechtalin V. A. Vlasenko N. I. Morozov B. D. Muriev V. A. Sudakov S. M. Svatkov I. G. Shcherbakova 《Measurement Techniques》1994,37(8):936-939
This article examines a 32-channel measuring-computing system for measuring dynamic strains, forces, pressures, and temperatures. It discusses the areas of application, structure, composition, main technical specifications, and software of the system.Translated from Izmeritel'naya Tekhnika, No. 8, pp. 49–51, August, 1994. 相似文献
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本文介绍了养护室温湿度控制仪的工作原理,以及在校检过程中其温度、湿度示值超差时的修正方法和使用注意事项。 相似文献
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A new method for measuring the cutoff wavelength of HE21, TE01, and TM01 modes in single-mode fibers is reported. The method is based on the difference in polarization between the HE11 and second-order modes launched in the offset condition. A single-polarization fiber several meters in length is used as a launching fiber to eliminate cladding mode disturbance and realize linear polarization launching into a test fiber. Good agreement between theoretical and measured cutoff wavelengths for fibers with various refractive-index profiles confirms the high accuracy of the method. A resolution of +/-0.005 microm is attained with the method. 相似文献
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Ehsani Mohammad Hossein Raoufi Tina 《Journal of Superconductivity and Novel Magnetism》2022,35(11):3457-3466
Journal of Superconductivity and Novel Magnetism - The critical behavior and Landau theory for La0.8-x SmxSr0.2MnO3(x = 0, 0.05, 01) manganites are investigated in detail around... 相似文献
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《Materials Science & Technology》2013,29(5):452-457
AbstractThe effects of laser surface hardening on AISI 01 tool steel samples were studied by changing the laser operating parameter combinations and the initial steel microstructure. Both melted and solid state transformed regions were produced, and then studied using optical microscopy, analytical electron microscopy, X-ray diffraction, and measurements of micro hardness to investigate the hardening mechanisms and the development of compressive residual stresses. The results indicate that hardened case depths up to 0·6 mm can be obtained using a laser beam operated at a power of 500 W and a scan rate of 2·1 mm s?1, but that different amounts of retained austenite and undissolved carbides are observed for different beam powers. Quenched and tempered AISI 01 steel samples, with initial hardness values in the range 30–40 HRC, are better suited for laser surface hardening compared with the samples with initial hardness of 48–50 HRC, because the formation of an over tempered region adjacent to the hardened zone can be avoided.MST/901 相似文献
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Quanmin YANG Yongquan LEI+ Changpin CHEN Jing WU Qidong WANG Dept. of Mater. Sci. Eng. Zhejiang Univresity Hangzhou China 《材料科学技术学报》1993,9(2):125-128
The thermal stability of amorphous ternary hydrides Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45) and their corre-sponding amorphous binary alloys Mg_(50)Ni_(50) and Mg_(30)Ni_(70) were studied with X-ray diffraction(XRD) and differential scanning calorimetry(DSC). Samples of the amorphous alloys were preparedby mechanical alloying and the amorphous hydrides were obtained by charging the alloys with gas-eous hydrogen at 3.0 MPa and 423 K. It was found that the amorphous hydrides released most oftheir hydrogen before the crystallization of the essentially hydrogen depleted amorphous alloy. Thecrystallization temperature of amorphous Mg_(50)Ni_(50)H_(54) elevated and that of amorphousMg_(30)Ni_(70)H_(45) did not change in relation to the original binary amorphous alloy. This is very excep-tional for amorphous hydrides. The reason for the effects of hydrogen absorption/desorption on thecrystallization of amorphous alloys was discussed. 相似文献
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针对两种新型稀土型储氢合金La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2的储氢特性进行研究分析。实验表明,相同温度下,La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2合金的PCT曲线基本重合,且都具有优良的吸氢动力学性能;相比之下,后者的滞后系数要小于前者,吸氢量较大,吸氢速率也较快,故其储氢性能较优。300次吸放氢循环实验结果表明,La0.5Y0.5Ni4.8Al0.2合金的吸氢动力学性能虽然略有下降,但抗粉化性能较好。 相似文献
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Chauhan B Shimpi S Mahadik KR Paradkar A 《Drug development and industrial pharmacy》2005,31(9):851-860
Single and multi-unit floating matrices of risedronate sodium were prepared using Gelucire® 43/01 by melt solidification and melt granulation technique, respectively. The controlled release floating matrices were evaluated for in vitro and in vivo floating ability and in vitro drug release. Effect of aging on Gelucire® 43/01 was evaluated by hot stage microscopy (HSM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), in vitro floating ability, and in vitro drug release. Multi-unit system obtained has shown initial burst release, which was suppressed in single unit system. Both single- as well as multi-unit systems showed increase in rate of drug release on aging due to changes in the properties of the Gelucire® 43/01. Multi-unit matrices obtained by melt granulation were relatively easier for scale up and advantageous if the initial burst release does not cause any significant clinical adversity. 相似文献
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B.M.P. Ferreira L.M.P. Pinheiro P.A.P. Nascente M.J. Ferreira E.A.R. Duek 《Materials science & engineering. C, Materials for biological applications》2009,29(3):806-813
The surfaces of poly(l-lactic acid) (PLLA) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) were modified by oxygen and nitrogen plasma treatments. The physical and chemical surface characteristics were evaluated by contact angle tests, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The plasma treatments caused an increase in both contact angle and roughening, altered the surface morphology, inserted polar groups, and, consequently, enhanced the hydrophilicity for both PLLA and PHBV polymers. 相似文献
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Experimental studies and analysis of acousto-optic diffraction in alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are given. Ultrasonic wave velocity, elastic compliance and stiffness coefficients, and piezo-optic and photoelastic coefficients of alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are determined. The acousto-optic figure of merit has been estimated for different possible geometries of acousto-optic interaction. It is shown that the acousto-optic figures of merit for alpha-BaB(2)O(4) crystals reach the value M(2)=(270 +/- 70) x 10(-15) s(3)/kg for the case of interaction with the slowest ultrasonic wave. The directions of propagation and polarization of those acoustic waves are obtained on the basis of construction of acoustic slowness surfaces. The acousto-optic diffraction is experimentally studied for alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals. 相似文献