M. Thambidurai N. Murugan N. Muthukumarasamy S. Agilan S. Vasantha R. Balasundaraprabhu
材料科学技术（英文）
Nanocrystalline CdS thin films have been deposited using precursors with different thiourea concentration onto glass substrates by sol-gel spin coating method. The crystalline nature of the films has been observed to be strongly dependent on thiourea concentration and annealing temperature. The CdS films are found to be nanocrystalline in nature with hexagonal structure. The grain size is found to be in the range of 7.6 to 11.5 nm depending on the thiourea concentration and annealing temperature. The high resolution transmission electron microscopy (HRTEM) results of the CdS films prepared using cadmium to thiourea molar ratio of 0.3:0.3 indicate the formation of nanocrystalline CdS with grain size of 5 nm. Fourier transform infrared (FTIR) analysis shows the absorption bands corresponding to Cd and S. The optical study carried out to determine the band gap of the nanostructured CdS thin films shows a strong blue shift. The band gap energy has been observed to lie in the range of 3.97 to 3.62 eV following closely the quantum confinement dependence of energy on crystallite radius. The dependence of band gap of the CdS films on the annealing temperature and thiourea concentration has also been studied. The photoluminescence (PL) spectra display two main emission peaks corresponding to the blue and green emissions of CdS.
关键词:
Sol-gel
,
CdS quantum dots
,
HRTEM.
朱良
,
王晶
,
李晓慧
,
锁红波
,
张亦良
材料研究学报
针对应力比对疲劳寿命影响的问题,以TC18钛合金堆焊成形(利用多层堆焊的方法制备)试样为研究对象,进行了3种应力比(R=0.5、R=0.06、R=-1)的疲劳实验,得出相应的疲劳极限,应用"应力幅值寿命模型"和"三参数寿命模型"得到6条S-N曲线.根据裂纹扩展速率与疲劳寿命的积分关系,以两种疲劳寿命数学模型为基础,系统地研究了应力比(R)与疲劳寿命曲线(S-N)的关系,提出了考虑应力比的疲劳寿命(R-S-N)数学模型.根据本文提出的修正公式,建立了适用TC18钛合金堆焊成形材料的两种R-S-N数学模型,结果表明:用应力幅值寿命模型可对中等疲劳寿命区进行准确的预测,而三参数寿命模型更适合中长寿命区域的预测.提出的两种R-S-N数学模型与实验值吻合良好,并可在工程上预测任意应力比下的疲劳寿命曲线.
关键词:
材料科学基础学科
,
应力比
,
疲劳寿命
,
疲劳极限
,
R-S-N数学模型
王德发
,
宋雅茹
,
胡玉萍
,
杨亦平
,
侯冬岩
色谱
doi:10.3321/j.issn:1000-8713.2003.04.027
利用卵类粘蛋白手性固定相高效液相色谱法直接拆分了S,S-和R,R-N-对甲基苯磺酰基-1,2-二苯基乙二胺(TsDPEN).研究了流动相中有机调节剂的种类和含量、缓冲溶液的酸度、盐浓度和流速等色谱条件对拆分结果的影响.结果表明,在25 ℃时,采用0.02 mol/L的磷酸二氢钾缓冲溶液(pH 4.56)(含20%(体积分数)乙腈)作流动相,流速0.4 mL/min,能得到最佳的基线分离.分离度和选择因子分别为2.67和2.23,流出时间在10 min之内.方法简单、快速.
关键词:
高效液相色谱
,
卵类粘蛋白柱
,
N-对甲基苯磺酰基-1,2-二苯基乙二胺
,
对映体分离
陈立志
,
张亚军
材料开发与应用
doi:10.3969/j.issn.1003-1545.2011.05.010
分别采用三点弯曲SE(B)与紧凑拉伸C(T)试样,通过-20℃的低温裂纹尖端张开位移CTOD断裂韧性试验及疲劳裂纹扩展速率da/dN试验,研究了S355N及S355N-Z25结构钢的裂纹启裂与扩展的抗力.研究结果表明:S355N钢抵抗裂纹启裂及前期扩展的能力比S355N-Z25钢强,但前者抵抗裂纹后期扩展的能力比后者弱；当应力强度因子范围,△K小于34.3MPa·√m时,S355N钢的疲劳抗力比S355N-Z25钢弱,当△K等于34.3MPa·√m时,两者具有相同的疲劳抗力,当△K大于34.3MPa·√m时,前者的疲劳抗力比后者强.研究结果对两种钢板在工程上应用及结构的安全评定提供了参考.
关键词:
S355N及S355N-Z25钢板
,
低温CTOD断裂韧性
,
疲劳裂纹扩展速率da/dN
,
裂纹启裂
,
裂纹扩展
,
抗力
张娟娟
,
高元安
,
叶健熠
,
张宗亮
材料开发与应用
doi:10.3969/j.issn.1003-1545.2003.05.010
测定某超硬不锈钢的接触疲劳P-S-N曲线,估计出试验应力S与试样寿命N之间函数关系式N=CS-m中的待定参数C和m,得出不同破坏概率(1%,5%,10%,50%)下试验应力S与寿命N的关系,为材料的使用和产品设计提供试验依据.
关键词:
接触疲劳
,
P-S-N曲线
,
应力
,
寿命
侯艳超
,
黄剑锋
,
周璇
,
曹丽云
,
吴建鹏
人工晶体学报
采用液相自组装法,以氯化钐( SmCl3·6H2O)和硫代硫酸钠(Na2S2O3·5H2O)为原料,在不同n(Sm3 )/n(S2O2-3)(物质的量比)条件下,于硅基板上制备了α-Sm2S3光学薄膜.利用X射线衍射仪(XRD)、光电子能谱分析(XPS)、原子力显微镜(AFM)和紫外-可见吸收光谱仪(UV-Vis)对SmS3薄膜的物相组成、表面形貌和光学性能进行了表征.结果表明:所制备的Sm2S3薄膜为α-Sm2S3,在一定范围内,随着n(Sm3+)/n(S2O2-3)的增加,α-Sm2S3薄膜的结晶性先增强后降低,并表现出(105)晶面取向生长的特征.紫外透射光谱分析表明,当n(Sm3+)/n(S2O2-3)=1∶2时,Sm2S3薄膜在可见光范围内透过率高达85％,禁带宽度为4.12 eV.
关键词:
Sm2S3薄膜
,
液相自组装
,
n(Sm3+)/n(S2O2-3)
苟国庆
,
黄楠
,
陈辉
,
孟立春
,
吴沛沛
材料科学与工艺
文章选取了我国某类型高速列车常用的A7N01S-T5铝合金材料,进行了恒载荷应力腐蚀试验,对A7N01S-T5材料的应力腐蚀机理、应力腐蚀强度因子K1SCC和裂纹生长机制进行了研究.结果表明,A7N01S-T5铝合金的应力腐蚀破坏敏感性很高,其临界应力场强度因子K1 SCC为5.2 MPa.m1/2,仅为断裂韧度K1 C的0.15,对应的临界应力门槛值б为123MPa,仅为拉伸强度бb0.27.裂纹断口面有明显的舌状凸起和凹坑的存在.A7N01S-T5铝合金的应力腐蚀裂纹以沿晶开裂为主,形貌呈树枝状,同时相邻二次裂纹之间有竞争生长的关系.
关键词:
高速列车
,
A7N01S-T5铝合金
,
应力腐蚀
,
K1SCC
Corrosion
Inhibition for carbon dioxide (CO2) corrosion of N80 steel by quaternary alkynoxymethyl amine (IMC-80-Q) in 3% sodium chloride (NaCl) solution was investigated under static and flowing conditions using a modified rotating disk apparatus. The effects of flow velocity and concentration of inhibitor on inhibition performance were performed using a weight-loss test, scanning electron microscope (SEM) observation, and electrochemical techniques including electrochemical impedance spectroscopy (EIS), linear polarization resistance, and polarization curves. The results showed that flow velocity had strong effects on the inhibitor performances. Inhibition efficiency (q) and polarization resistance (R) exhibited the peak-value phenomenon at an inhibitor concentration of 150 mg/L when flow velocity was less than 5 m/s, in contrast with the 300 mg/L when flow velocity was higher than 5 m/s. Critical flow velocity in the uninhibited solution was between 4 m/s and 5 m/s.
关键词:
carbon dioxide corrosion;criticalflow velocity;flow effect;inhibitor;N80 steel;peak-value phenomenon;impedance plane displays;rotating cylinder;stability conditions;steady-state;pipe-flow;electrode;derivatives;thiourea;velocity
易兵
,
谢治民
,
党立敏
应用化学
doi:10.3969/j.issn.1000-0518.2007.02.023
采用NaBH4/I2还原体系,在THF溶剂中,对(3S,4S)-N-苄基-3,4-二羟基氢化吡咯的合成方法进行了改进,着重探讨了原料配比,反应时间和还原剂类型等因素对产品收率的影响.在优化的反应条件下,底物、NaBH4和I2的摩尔比为1:5:1.67,回流下反应时间6 h,产品收率达70%.通过1H NMR、13C NMR等测试技术进行了表征,结果与目标化合物一致.与传统的合成方法相比,该法具有相对经济,操作简便,可大量制备的特点.
关键词:
(3S,4S)-N-苄基二羟基氢化吡咯
,
NaBH4/I2
,
合成
