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PCBA上焊盘焊接不良原因分析 被引量:1
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作者 吕俊杰 《科技创新与应用》 2017年第11期116-116,共1页
PCBA上锡不良的现象,通过对失效焊盘进行表面观察、剖面分析、表面成分分析等手段查找失效原因。结果表明:由于失效焊盘在过炉前被氧化,焊盘表面沉锡层厚度急剧减薄,从而导致焊盘上锡不良。从而总结出在回流焊接工艺中PCBA焊盘上锡不良... PCBA上锡不良的现象,通过对失效焊盘进行表面观察、剖面分析、表面成分分析等手段查找失效原因。结果表明:由于失效焊盘在过炉前被氧化,焊盘表面沉锡层厚度急剧减薄,从而导致焊盘上锡不良。从而总结出在回流焊接工艺中PCBA焊盘上锡不良的原因由设计、材料、设备和工艺所合成的。 展开更多
关键词 PCBA 上锡不良 表面sem FIB剖面
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液态CO_(2)对304不锈钢的腐蚀规律研究
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作者 商永滨 李欣欣 +3 位作者 梁右才 赵飞 赵大庆 董巍 《石油和化工设备》 CAS 2021年第2期91-96,共6页
利用电化学工作站和低温高压釜完成了304不锈钢在液态CO_(2)条件下的腐蚀行为实验,利用Tafel曲线、交流阻抗谱图、Matt-Schottky曲线分析了304不锈钢在液态CO_(2)浸泡下的腐蚀规律,通过电镜扫描表面SEM形貌也验证了相同的腐蚀规律,随压... 利用电化学工作站和低温高压釜完成了304不锈钢在液态CO_(2)条件下的腐蚀行为实验,利用Tafel曲线、交流阻抗谱图、Matt-Schottky曲线分析了304不锈钢在液态CO_(2)浸泡下的腐蚀规律,通过电镜扫描表面SEM形貌也验证了相同的腐蚀规律,随压力升高、温度降低,腐蚀程度均呈现加重的趋势,抗拉强度变化不大,而屈服强度则显著增大,材料发生脆性断裂的趋势增大;含O_(2)杂质情况下会大大减轻304不锈钢的腐蚀程度。 展开更多
关键词 液态CO2 Tafel曲线 阻抗谱图 Matt-Schottky曲线 表面sem形貌
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Effects of Steam Heat Treatment on the Surface Contact Angle of Chinese Fir 被引量:1
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作者 高伟 罗建举 +3 位作者 石世亨 李荣册 卢佩 郭玺 《Agricultural Science & Technology》 CAS 2014年第1期127-131,共5页
The aim of this study was investigate the effects of heat treatment on the contact angle of Chinese fir, and the indicators affecting the change of contact an-gle change. It was determined that the duration of treatme... The aim of this study was investigate the effects of heat treatment on the contact angle of Chinese fir, and the indicators affecting the change of contact an-gle change. It was determined that the duration of treatment had significant effect on the change curves of contact angle of Chinese fir wood due to the change curves of contact angle became more centralized and orderly after the specimens heat treated at 180 ℃. Compared with the untreated wood, the contact angle in-creased from 51&#176; to 124&#176; after 4 h treatment, and hydroxyl absorbance of hy-drophilic functional groups decreased from 2.08 to 1.63, while carbonyl absorbance from 0.92 to 0.62. The surface roughness has not significant influence on the con-tact angle. Heat treatment of the Chinese fir caused surface morphological change, which produced hol owed-out phenomenon. The increased surface contact angle caused by heat treatment can be used for outdoor and sauna facilities. 展开更多
关键词 Chinese fir Contact angle Steam heat treatment Surface roughness FTIR analysis sem observation
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Observation and Comparison of Pollen Submicroscopic Morphology of Seven Mulberry(Morus alba Linn.) Cultivars
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作者 胡德昌 张萍 +3 位作者 王艳杰 左进城 王照红 陈传杰 《Agricultural Science & Technology》 CAS 2012年第11期2261-2264,共4页
[Objective] This study aimed to investigate the submicroscopic structure and morphological characteristics of mulberry pollen. [Method] Mulberry pollen of seven cultivars were treated by glutaraldehyde fixing, alcohol... [Objective] This study aimed to investigate the submicroscopic structure and morphological characteristics of mulberry pollen. [Method] Mulberry pollen of seven cultivars were treated by glutaraldehyde fixing, alcohol gradient dehydration, freeze-drying and metal plating to observe the size and surface ornamentation under the scanning electron microscope (SEM). [Result] The pollen surface characteristics and ornamentation were clearly visible, indicating that this method is suitable for SEM observation of mulberry pollen; experimental mulberry pollen was nearly spher- ical, with two germination apertures and processes on aperture membrane; polar axis was 15.99-22.63 μm long, and equatorial axis was 14.98-20.78 μm long; the pollen volume of "Yu No.2' was the maximum, while that of "Jinxuan No.7' was the minimum; the surface of mulberry pollen showed smooth and tumor-like protuberance ornamentations, covered with different densities of particles. [Conclusion] Glutaralde- hyde fixative-alcohol gradient dehydration is an ideal method for morphological char- acteristics of mulberry pollen. This study may provide useful information for palynology identification of Morus plants or even species-level systematic classification. 展开更多
关键词 MULBERRY POLLEN Submicroscopic morphology
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锈蚀终结剂涂层的转化过程及其电化学行为 被引量:1
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作者 席发臣 邹冠驰 +2 位作者 宋轶黎 李志宝 雍兴跃 《现代涂料与涂装》 CAS 2014年第4期8-9,28,共3页
采用扫描电镜对锈蚀终结剂涂层的表面形貌进行分析,采用原子力显微镜技术研究了锈蚀终结剂涂层的转化过程。同时,利用电化学方法,研究了锈蚀终结剂涂层在腐蚀介质中的电化学行为。结果表明,在含锈蚀终结剂的涂层中,确实在发生一些化学反... 采用扫描电镜对锈蚀终结剂涂层的表面形貌进行分析,采用原子力显微镜技术研究了锈蚀终结剂涂层的转化过程。同时,利用电化学方法,研究了锈蚀终结剂涂层在腐蚀介质中的电化学行为。结果表明,在含锈蚀终结剂的涂层中,确实在发生一些化学反应,反应结果使得锈蚀终结剂涂层最终融为一体,成为均匀相。随着浸泡时间的延长,锈蚀终结剂涂层在开始阶段,其电化学反应阻抗随着浸泡时间增加而增大,当其浸泡超过48 h之后,随着浸泡时间的增加,电化学反应阻抗随着浸泡时间减小,耐蚀性降低。表明锈蚀终结剂在还原性环境中有更好的抗腐蚀作用,且需要配套防腐涂层才能具有很好的耐蚀性。 展开更多
关键词 锈蚀终结剂 转化过程 电化学行为 sem表面分析 AFM形貌 交流阻抗谱
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Wettability and surfactivity of sodium phosphate surfactants in strong alkali solutions 被引量:4
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作者 陈胜慧 董金凤 《Journal of Central South University》 SCIE EI CAS 2010年第5期924-929,共6页
The wettability,surfactivity and the correlation between wettability and surfactivity of sodium diethylhexylphosphate,sodium diethylhexyl polyoxyethylene phosphate and their complex in NaOH solutions were studied.A co... The wettability,surfactivity and the correlation between wettability and surfactivity of sodium diethylhexylphosphate,sodium diethylhexyl polyoxyethylene phosphate and their complex in NaOH solutions were studied.A complex alkali resistant phosphate surfactant with good permeability was prepared.The wettability of surfactants was investigated by measuring the immersion time,sinking time and capillary effects of nature cotton grey fabric in NaOH solutions.The surfactivity of the surfactants was characterized by measuring the surface tension.The effect of the complex on the surface appearance of cotton grey fabric was also investigated with a scanning electron microscope(SEM) .The results show that all the surfactants exhibit good wettability for cotton grey fabric in 0.5-5.0 mol/L of NaOH solutions,the complex system exhibits better wettability in 5.0-7.0 mol/L of NaOH solutions,in comparison with either corresponding single surfactant component employed,and wettability is well correlative with the surfactivities of the surfactant.SEM images indicate that the cotton grey fabric is well wetted by the alkaline surfactant solution and the quality of fabric is improved. 展开更多
关键词 sodium diethylhexylphosphate sodium diethylhexyl polyoxyethylene phosphate WETTABILITY surfactivity ALKALI SURFACTANT
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Synthesis of ordered mesoporous manganese titanium composite oxide catalyst for catalytic ozonation
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作者 Chaofei Fei Dan Li +2 位作者 Xian Mao Yu Guo Wenheng Jing 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第9期1862-1872,共11页
In this account,highly ordered mesoporous MnO_x/TiO_2composite catalysts with efficient catalytic ozonation of phenol degradation were synthesized by the sol–gel method.The surface morphology and properties of the ca... In this account,highly ordered mesoporous MnO_x/TiO_2composite catalysts with efficient catalytic ozonation of phenol degradation were synthesized by the sol–gel method.The surface morphology and properties of the catalysts were characterized by several analytical methods,including SEM,TEM,BET,XRD,FTIR,and XPS.Interestingly,Mn doping was found to improve the degree of order,and the ordered mesoporous structure was optimized at 3%doping.Meanwhile,MnO_xwas highly dispersed in the ordered mesoporous materials to yield good catalytic ozonation performance.Phenol could completely be degraded in 20 min and mineralized at 79%in 60 min.Thus,the catalyst greatly improved the efficiency of degradation and mineralization of phenol when compared to single O_3or O_3+TiO_2.Finally,the reaction mechanism of the catalyst was discussed and found to conform to pseudo-first-order reaction dynamics. 展开更多
关键词 Ordered mesoporous MNOX Catalytic ozonation Pseudo-first-order reaction
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ZnO/ P(VDF-TrFE)纤维薄膜的制备及压电性能研究
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作者 吴文涛 《中国科技期刊数据库 工业A》 2022年第6期213-216,共4页
基于共聚物聚偏氟乙烯-三氟乙烯 P(VDF-TrFE)的高性能柔性压电薄膜材料,研究ZnO/ P(VDF-TrFE)纤维薄膜的制备及压电性能,通过静电纺丝法制备柔性薄膜,并通过扫描电子显微镜对合成的柔性薄膜进行SEM表面形貌表征分析、傅里叶红外数据分... 基于共聚物聚偏氟乙烯-三氟乙烯 P(VDF-TrFE)的高性能柔性压电薄膜材料,研究ZnO/ P(VDF-TrFE)纤维薄膜的制备及压电性能,通过静电纺丝法制备柔性薄膜,并通过扫描电子显微镜对合成的柔性薄膜进行SEM表面形貌表征分析、傅里叶红外数据分析和自建的压电相应测试模块等。结果表明:P(VDF-TrFE)在高转速的静电纺丝法制备薄膜将具有更高的统一曲度,且随着ZnO的浓度增加,虽然其统一曲度较好,但是其平顺性破坏,逐渐出现了团聚的现象。在横向实验的比较过程中发现, P(VDF-TrFE)掺杂3%ZnO其β相的相对含量值较高,且其表现出了较好的压电性能,其d33达到了26。 展开更多
关键词 聚偏氟乙烯-三氟乙烯 静电纺丝 sem表面形貌 傅里叶红外数据分析 压电特性
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A Method for Calculating Fractal Dimension of Amicrons and Fractal Simulation of Boundary Micro-Topography
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作者 LI Jin-ping GAI Guo-sheng +2 位作者 ZHENG Zhou-shun HAO Xiang-yang YANG Yu-fen 《Journal of China University of Mining and Technology》 2006年第2期193-195,199,共4页
A simple and practical method to calculate the fractal dimension (FD) of amicron's projective surface profile based on fractal theory is proposed. Taking AI(OH)3 material particles as an example, the scanning ele... A simple and practical method to calculate the fractal dimension (FD) of amicron's projective surface profile based on fractal theory is proposed. Taking AI(OH)3 material particles as an example, the scanning electron microscope (SEM) photos of particles were processed using an image.processing software (IPS) Photoshop. Taking the pixel as a fixed yardstick with the enlargement of the size of the particle image, the box-dimension and circumference-area (C-S) methods were used to calculate the FD of the surface profile of the particle. The FD of 1.2623 of the classic Koch curve is obtained, which approximates the true value of 1.2628. The complexities of the object's boundary and surface micro-topography are simulated successfully by a generator method. 展开更多
关键词 fractal dimension amicron MICRO-TOPOGRAPHY surface profile quantitative characterization fractal simulation
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